“Partial” Glow Plug Controller Bypass

[stick_witch]

So, I did a manual bypass of the glow plug controller with a switch in the cab actuating the solenoid rather than the controller. But, I like and still want the functionality of the controller’s ability to detect the temp of the gp’s, when to turn them on and off, and the “wait to start” light telling me when the gp’s are warm enough to start the engine, so I wanted to find an alternate way to incorporate the controller without it actually “controlling” the gp’s and the solenoid. Here’s what I came up with.

First things first though, for those who don’t know already, you need to know a little bit about how the glow plug controller on these trucks work so here is a brief description and diagram.

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The controller essentially uses the resistance of the glow plugs and gp harness to determine their temperature. Heat = more resistance, so as the resistance increases the controller assumes their temperature and cycles the wts light and gp’s on or off accordingly. First, the controller turns on the wts light and actuates the gp solenoid and gp’s as soon as it gets power from the ignition being turned to the “run” position. This initiates the pre-glow cycle, which warms the glow plugs up to starting temp. Once the glow plugs reach starting temp, which usually takes anywhere from 3-15 seconds, the controller turns off the wts light, but THE GLOW PLUGS STAY ON. This is now the after-glow cycle. Best way to see this is with a voltmeter to plug into your 12v socket in a truck with a stock gp system. Voltage drops to ~11.2v when you turn the key, indicating the gp’s are drawing power, and then it stays there even after the wts light goes out. It may creep up slowly to maybe ~11.4v because the gp’s draw less as they get warmer, but thats about it. The controller does not cycle the gp’s on and off during this time, which is what some will say, but is just not correct. If this were the case the voltage would vary and the solenoid would click on and off after the wts turns off and they just don’t on these trucks when functioning properly. This cycle lasts really anywhere under a minute, totally dependent on glow plug temperature. Then, the controller toggles the solenoid back off to keep them from burning out.

This is why people have a hard time starting their idi’s, because they try to crank it over right after the wts light goes out when the gp’s are due to run for a lot longer. Its also why many guys use their manual gp systems completely wrong. They will only run their glow plugs in cycles of no more than 15 seconds when they can run, and are supposed to run them longer and should be able to start their rig in one full cycle, rather than many small cycles. But, it’s impossible to determine how long you should cycle them after the pre-glow cycle because first the controller is bypassed so you have no way of knowing when the pre-glow cycle ends, or when the after-glow cycle ends, and second because it varies so greatly depending on temperature and how heat soaked the plugs are already, and if you can’t determine the temperature of the plugs, you can’t determine the duration. So, without some sure way of knowing, 15-20sec cycles are really the only safe answer, which is why that is what people do and say to do. Unless, of coarse, you use the controller to your advantage, which is what I intend to do.

So, what I ended up doing was this. If you refer to the diagram, the white wire from the controller is what toggles the solenoid via a gate inside the controller which is on the ground side of the gp circuit. So first I took this wire off its post on the solenoid (don’t cut it!), disconnecting the controller from the solenoid. Now the controller no longer controls the gp’s and solenoid actuation.

All that must be done now is to run a wire from the cab to the small ground post on the gp solenoid, plug it into a momentary switch in the dash, and run a ground wire from the switch to some place on the frame, to complete the low amp circuit of the gp solenoid, and then bam! You have a successful gp bypass.

Now to complete the “partial” bypass aspect of this I went this route. I installed 2 small indicator lights above the wts light in the cab.

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The one on the left will be my “gp on” indicator, which will be hooked up to the gp harness post on the controller after the bus bar, and grounded in the cab to the frame to indicate that there is power coming from the gp solenoid to the gp harness. This is a great indicator if you’re solenoid goes out in the future since your solenoid will no longer do the infamous clicky clicky.

The light on the right will indicate the end of the after-glow cycle and that the controller is communicating to turn the gp’s off.

To do this you must first run a hot wire to the light in the cab. I chose to get this from the positive low amp post (small post) on the gp solenoid which gets its power from the ignition solenoid when the key is turned. Then you must run a wire from the light back to the controller via a separate wire to be mated with the white wire from the controller I was talking about earlier. This must be done because the white wire doesn’t emit power when the controller gate is closed, its merely a ground side gate that is grounded via the controller’s own ground wire. So you must first take power from someplace else, to create a functioning circuit to take advantage of the controller’s internal gate.

The wts light will keep its normal function, indicating the start and end of the pre-glow cycle. This light gets it’s info from the dark blue wire running from the controller to a black and green sealed plug and then to the cab. Do not cut this wire or unplug it if you want this function.

That’s essentially it, now you have a partial bypass in that you physically control the glow plugs, but you are also putting your controller to work for you. No more guessing and counting seconds in your head.

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***IMPORTANT!
For this to work properly, you need to have your glow plug switch/button held on before you turn the ignition key and keep it held on for the remainder of the gp cycle. This tricks the controller that it is functioning normally (don’t worry, the gp’s won’t turn on unless the key is in the “run” position). If you don’t the wts in particular won’t function right. It will come on very briefly and then turn off and won’t come back on until you cycle the ignition again. The after-glow cycle light on the other hand should and seems to function regardless, but it’ll just blink on and off if you aren’t running glow plugs until it times out.

For this reason I use a switch that has an upward momentary latch and a downward locking latch. For morning cold starts I just flip the switch to the locking position before i turn the key, and then when my after-glow cycle light goes out I promptly flip it off. And then when I just need a little bit of glow for any reason I hold the momentary switch on till the wts light goes out and then I turn the key.

If you do use a normal switch, make sure you monitor the “gp on” light so you don’t accidentally leave the gp’s on. Also its good to monitor to make sure your solenoid isn’t sticking for some reason and burning up your gp’s.

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[Farmer Rock]

I used the same diagrams when I did the manual GPs on my trucks. I like the idea, but my personal preference, is that removing the controller entirely and running on just the switch and solenoid is a lot more simple. At first I used a push button switch,but now I use a lighted toggle switch instead. Most of the time when it's cold, I use the block heater, so I only need like 5 seconds on plugs, but without the heater, I double cycle them ,10 seconds on, 20 seconds off, then 10 seconds on and she fires right up. It's sound more complicated then it really is. I removed the WTS and water in fuel lamps, and made a switch panel to fit in there for my GPs and high idle.
Very good write up BTW!



Rock

 

[franklin2]

So, I did a manual bypass of the glow plug controller with a switch in the cab actuating the solenoid rather than the controller. But, I like and still want the functionality of the controller’s ability to detect the temp of the gp’s, when to turn them on and off, and the “wait to start” light telling me when the gp’s are warm enough to start the engine, so I wanted to find an alternate way to incorporate the controller without it actually “controlling” the gp’s and the solenoid. Here’s what I came up with.

First things first though, for those who don’t know already, you need to know a little bit about how the glow plug controller on these trucks work so here is a brief description and diagram.

You must be registered for see images attach

The controller essentially uses the resistance of the glow plugs and gp harness to determine their temperature. Heat = more resistance, so as the resistance increases the controller assumes their temperature and cycles the wts light and gp’s on or off accordingly. First, the controller turns on the wts light and actuates the gp solenoid and gp’s as soon as it gets power from the ignition being turned to the “run” position. This initiates the pre-glow cycle, which warms the glow plugs up to starting temp. Once the glow plugs reach starting temp, which usually takes anywhere from 3-15 seconds, the controller turns off the wts light, but THE GLOW PLUGS STAY ON. This is now the after-glow cycle. Best way to see this is with a voltmeter to plug into your 12v socket in a truck with a stock gp system. Voltage drops to ~11.2v when you turn the key, indicating the gp’s are drawing power, and then it stays there even after the wts light goes out. It may creep up slowly to maybe ~11.4v because the gp’s draw less as they get warmer, but thats about it. The controller does not cycle the gp’s on and off during this time, which is what some will say, but is just not correct. If this were the case the voltage would vary and the solenoid would click on and off after the wts turns off and they just don’t on these trucks when functioning properly. This cycle lasts really anywhere under a minute, totally dependent on glow plug temperature. Then, the controller toggles the solenoid back off to keep them from burning out.

This is why people have a hard time starting their idi’s, because they try to crank it over right after the wts light goes out when the gp’s are due to run for a lot longer. Its also why many guys use their manual gp systems completely wrong. They will only run their glow plugs in cycles of no more than 15 seconds when they can run, and are supposed to run them longer and should be able to start their rig in one full cycle, rather than many small cycles. But, it’s impossible to determine how long you should cycle them after the pre-glow cycle because first the controller is bypassed so you have no way of knowing when the pre-glow cycle ends, or when the after-glow cycle ends, and second because it varies so greatly depending on temperature and how heat soaked the plugs are already, and if you can’t determine the temperature of the plugs, you can’t determine the duration. So, without some sure way of knowing, 15-20sec cycles are really the only safe answer, which is why that is what people do and say to do. Unless, of coarse, you use the controller to your advantage, which is what I intend to do.

So, what I ended up doing was this. If you refer to the diagram, the white wire from the controller is what toggles the solenoid via a gate inside the controller which is on the ground side of the gp circuit. So first I took this wire off its post on the solenoid (don’t cut it!), disconnecting the controller from the solenoid. Now the controller no longer controls the gp’s and solenoid actuation.

All that must be done now is to run a wire from the cab to the small ground post on the gp solenoid, plug it into a momentary switch in the dash, and run a ground wire from the switch to some place on the frame, to complete the low amp circuit of the gp solenoid, and then bam! You have a successful gp bypass.

Now to complete the “partial” bypass aspect of this I went this route. I installed 2 small indicator lights above the wts light in the cab.

You must be registered for see images attach

The one on the left will be my “gp on” indicator, which will be hooked up to the gp harness post on the controller after the bus bar, and grounded in the cab to the frame to indicate that there is power coming from the gp solenoid to the gp harness. This is a great indicator if you’re solenoid goes out in the future since your solenoid will no longer do the infamous clicky clicky.

The light on the right will indicate the end of the after-glow cycle and that the controller is communicating to turn the gp’s off.

To do this you must first run a hot wire to the light in the cab. I chose to get this from the positive low amp post (small post) on the gp solenoid which gets its power from the ignition solenoid when the key is turned. Then you must run a wire from the light back to the controller via a separate wire to be mated with the white wire from the controller I was talking about earlier. This must be done because the white wire doesn’t emit power when the controller gate is closed, its merely a ground side gate that is grounded via the controller’s own ground wire. So you must first take power from someplace else, to create a functioning circuit to take advantage of the controller’s internal gate.

The wts light will keep its normal function, indicating the start and end of the pre-glow cycle. This light gets it’s info from the dark blue wire running from the controller to a black and green sealed plug and then to the cab. Do not cut this wire or unplug it if you want this function.

That’s essentially it, now you have a partial bypass in that you physically control the glow plugs, but you are also putting your controller to work for you. No more guessing and counting seconds in your head.

You must be registered for see images attach

***IMPORTANT!
For this to work properly, you need to have your glow plug switch/button held on before you turn the ignition key and keep it held on for the remainder of the gp cycle. This tricks the controller that it is functioning normally (don’t worry, the gp’s won’t turn on unless the key is in the “run” position). If you don’t the wts in particular won’t function right. It will come on very briefly and then turn off and won’t come back on until you cycle the ignition again. The after-glow cycle light on the other hand should and seems to function regardless, but it’ll just blink on and off if you aren’t running glow plugs until it times out.

For this reason I use a switch that has an upward momentary latch and a downward locking latch. For morning cold starts I just flip the switch to the locking position before i turn the key, and then when my after-glow cycle light goes out I promptly flip it off. And then when I just need a little bit of glow for any reason I hold the momentary switch on till the wts light goes out and then I turn the key.

If you do use a normal switch, make sure you monitor the “gp on” light so you don’t accidentally leave the gp’s on. Also its good to monitor to make sure your solenoid isn’t sticking for some reason and burning up your gp’s.

You must be registered for see images attach

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Your theory of operation has some flaws. Do I know all about the engineering of the glowplug controller? No. But I can tell some things by the way it acts.

You are correct, the controller determines the amount of glow time by the resistance of the glowplug circuit. This in itself is the most serious flaw in this system. One bad glowplug and you are sunk, it's not going to start because the controller turns the plugs off too early. Poor wiring connections to the gowplugs also cause extra resistance. Thus the reason most people go to manual control. If you have manual control, the engine will start with at least two bad glowplugs, been there done that. How many bad ones you can have and still start I don't know. The engine is not happy about it, but it will start. You would be stuck if you only had the controller power the glowplugs.

And when the glowplugs cycle, anyone can tell you their voltage drops way below 11.2 volts. The factory dash gauge may not be that accurate, but it says the voltage when the glowplugs are cycling is more near 8 volts. I can tell you from experimentation, it's best to glow the plugs and then use the starter motor. The starter motor slows noticeably if you hold the glowplug button and crank at the same time. And I see no advantage to glowing the plugs after the engine starts. Once the engine starts, you are good to go, no need for the plugs anymore.

 

[Booyah45828]

I think all of this is just extra steps to what should be a simple process.

I don't know how long you can hold a zd9 on without it having issues. Everything that I've read is that it is a 6 volt plug and is NOT self-limiting. If that's all the case, I don't think they should be lit for minutes on end in a non-running engine. IF the engine is running, then there is air movement around them, so they might not get as hot as they would without the air movement. Correct me if I'm wrong.

Best thing I've done is install 60g plugs, a good stancor relay, and a pushbutton. I can guess pretty well if and how long my plugs should be on. And if I'm wrong, the self-limiting feature of the plug should protect me. I've also moved the lead for the WTS light onto the same relay terminal as the plugs. So if the light is on, the plugs are receiving power. Now the light works as a diagnostic for a failed relay, or if the pushbutton circuit shorts to ground somehow.

And I see no advantage to glowing the plugs after the engine starts. Once the engine starts, you are good to go, no need for the plugs anymore.

*Starts and is running smoothly. Any afterglow outside of that is there for emissions IMO. The rest you're spot on about.

 

[Black dawg]

Your theory of operation has some flaws. Do I know all about the engineering of the glowplug controller? No. But I can tell some things by the way it acts.

You are correct, the controller determines the amount of glow time by the resistance of the glowplug circuit. This in itself is the most serious flaw in this system. One bad glowplug and you are sunk, it's not going to start because the controller turns the plugs off too early. Poor wiring connections to the gowplugs also cause extra resistance. Thus the reason most people go to manual control. If you have manual control, the engine will start with at least two bad glowplugs, been there done that. How many bad ones you can have and still start I don't know. The engine is not happy about it, but it will start. You would be stuck if you only had the controller power the glowplugs.

And when the glowplugs cycle, anyone can tell you their voltage drops way below 11.2 volts. The factory dash gauge may not be that accurate, but it says the voltage when the glowplugs are cycling is more near 8 volts. I can tell you from experimentation, it's best to glow the plugs and then use the starter motor. The starter motor slows noticeably if you hold the glowplug button and crank at the same time. And I see no advantage to glowing the plugs after the engine starts. Once the engine starts, you are good to go, no need for the plugs anymore.

Just went and tested two different 7.3 trucks.....around 15 degrees......both dropped to just under 11v battery voltage at initial key(max amp draw from plugs) on glow plug cycle. Both trucks have 8 good glow plugs and good wiring.

 

[mblaney]

What is the real purpose of this? I understand switching between manual and auto, but why? Are you trying to disable the GP's if they are not needed?

One thing I added to my GP controller is an oil pressure switch. As soon as I have oil pressure the GP controller is shut off. I think this really extends the life of the GP's. Once I had a problem at -25C where the engine quit as soon the GP's turned off, but I simply shorted the switch and let it run normally.

 

[stick_witch]

Your theory of operation has some flaws. Do I know all about the engineering of the glowplug controller? No. But I can tell some things by the way it acts.

You are correct, the controller determines the amount of glow time by the resistance of the glowplug circuit. This in itself is the most serious flaw in this system. One bad glowplug and you are sunk, it's not going to start because the controller turns the plugs off too early. Poor wiring connections to the gowplugs also cause extra resistance. Thus the reason most people go to manual control. If you have manual control, the engine will start with at least two bad glowplugs, been there done that. How many bad ones you can have and still start I don't know. The engine is not happy about it, but it will start. You would be stuck if you only had the controller power the glowplugs.

And when the glowplugs cycle, anyone can tell you their voltage drops way below 11.2 volts. The factory dash gauge may not be that accurate, but it says the voltage when the glowplugs are cycling is more near 8 volts. I can tell you from experimentation, it's best to glow the plugs and then use the starter motor. The starter motor slows noticeably if you hold the glowplug button and crank at the same time. And I see no advantage to glowing the plugs after the engine starts. Once the engine starts, you are good to go, no need for the plugs anymore.

Yeah I understand your critique on the controller, and I totally agree with you there. Thats why I did a manual bypass, if you read, the controller has no control of my gp solenoid actuation, thats done by my manual switch in the cab. All the controller is doing now is lighting up my lights in the dash merely for a point of reference rather than sitting there doing nothing. I don’t have to do what it says. Plus, you can now easily tell when either your solenoid or one or a couple of your glow plugs are out because either my “gp on” light won’t come on with my switch, or my “after-glow cycle” light will flicker on and off, just like the solenoid would click on the stock systems. So when my controller goes out or a couple of my gp’s, my system still works AND I have an instant and easy reference point to tell if my gp system is healthy or not. So I don’t quite understand how your critique correlates to my system. I understand the flaws of the stock controller system, thats why I bypassed it, so im the one in control, not the controller.

As far as draw of the gp’s... heres the thing... every truck is different. I use an alternate voltmeter mounted in my dash because the stock gauge is inaccurate (i have tested with a normal voltmeter straight from my batteries as well) , I have 2 brand new group 65 interstate batteries, a 3g 130 amp alternator and my gp’s are all new motorcraft plugs. My solenoid is brand new and I just re did the gp harness. My truck drops to 11.2v and has always dropped to 11.2v when cycling the gp’s. When i run the starter it drops to 8-9v, thats my experience. My gp’s and controller have always worked normally and my truck starts great.

Lastly, the gp’s are supposed to run for a couple seconds while the truck starts and runs, thats why it’s called the “after-glow cycle”. Of course they don’t have to, but they do this to help smooth out the engine when starting, since they’ll tend to only start firing on a few cylinders at a time and progressively cylinders will join in, which creates the rattle and shake during cold starts due to imbalances. The gp’s cycling during this time helps to get all cylinders firing quicker. If you observe a stock gp system, you will see that if you start the truck sometime after the wts light goes off and before the controller shuts down the gp’s, the gp’s will actually be running the first few seconds of the truck running then go off.


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[stick_witch]

I think all of this is just extra steps to what should be a simple process.

I don't know how long you can hold a zd9 on without it having issues. Everything that I've read is that it is a 6 volt plug and is NOT self-limiting. If that's all the case, I don't think they should be lit for minutes on end in a non-running engine. IF the engine is running, then there is air movement around them, so they might not get as hot as they would without the air movement. Correct me if I'm wrong.

Best thing I've done is install 60g plugs, a good stancor relay, and a pushbutton. I can guess pretty well if and how long my plugs should be on. And if I'm wrong, the self-limiting feature of the plug should protect me. I've also moved the lead for the WTS light onto the same relay terminal as the plugs. So if the light is on, the plugs are receiving power. Now the light works as a diagnostic for a failed relay, or if the pushbutton circuit shorts to ground somehow.



*Starts and is running smoothly. Any afterglow outside of that is there for emissions IMO. The rest you're spot on about.

Yeah, its definitely complicated, I 100% agree with you there, and at first my system operated just like yours. I just hated the guessing game of trying to figure out how long I can or can’t run my gp’s. I live in Alaska so I’m cold COLD starting my truck most days if I’m not on the block heater, so cycling my plugs on for 15 sec, back off, then on again over and over just doesn’t work for me. With the stock system running my gp’s in refrence to my voltmeter my truck started and worked perfectly all the time no matter the temperature. So for that reason I wanted to fine a way to incorporate the controller as a reference tool to me rather than have it sit there doing nothing.

To my knowledge, no one has done a write up on how to do this so thats why it’s here and why its called a “partial” bypass. If people don’t want to go through the trouble than I would happily steer them towards the thousands of other threads on how to do a normal, outright bypass of the controller.


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[stick_witch]

Just went and tested two different 7.3 trucks.....around 15 degrees......both dropped to just under 11v battery voltage at initial key(max amp draw from plugs) on glow plug cycle. Both trucks have 8 good glow plugs and good wiring.

Like I told franklin2, every truck is different and every voltmeter instrument is different, my truck when I got it with the old batteries and stock gp’s, wiring, controller, solenoid, everything, ran ~10.8v when the gp’s cycled and didn’t start worth a crap.

Now I run a 130amp 3g alternator, 2 brand new group 65 interstate batteries, new battery terminals and cable, new motorcraft zd9 gp’s, new solenoid, redone gp harness, and all good wiring. Truck starts easy, even when it goes subzero and has been sitting awhile, and gp’s drop to ~11.2v every time when I cycle the gp’s according to my digital voltmeter in my cab coming off the 12v socket. Thats my experience with my truck.

I know guys want to find any reason their system is better than someone elses, but trust me guys, I live in Alaska... my truck doesn’t start EVER without a perfect functioning gp system[emoji23]. My truck drops only to 11.2v because my batteries are brand spankin new, quality batteries that I baby, my charging system is leaps and bounds better than any stock idi, and I don’t let my truck sit around. The only thing there is to debate is whether my voltmeter is more or less accurate, but I’ve tested this with a normal multimeter on the batteries and it says the same thing... so idk, make of it what you guys want...

I’m just here to share my unique “partial” bypass system because I haven’t heard anyone do a write up in it. Or seen anyone do it for that matter.


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[stick_witch]

What is the real purpose of this? I understand switching between manual and auto, but why? Are you trying to disable the GP's if they are not needed?

One thing I added to my GP controller is an oil pressure switch. As soon as I have oil pressure the GP controller is shut off. I think this really extends the life of the GP's. Once I had a problem at -25C where the engine quit as soon the GP's turned off, but I simply shorted the switch and let it run normally.

No, I think you’re misunderstanding what my system is doing. There is nothing auto about it, it is 100% manual. The controller does not ever communicate directly to the gp solenoid, it only gathers information and power from the gp’s and solenoid and communicates that information to me via my wts light, “gp on” light, and “after-glow cycle” light”. The use for this is so I have a reference of how warm my gp’s are and when it is absolutely mandatory that I turn them off, and also so I can easily monitor if my solenoid is sticking or faulty, or if my gp’s are starting to fail.

All it is is a normal gp bypass, and all that I’m doing with the extra steps is incorporating the controller as a timing reference and a protection measure so that I can run the gp’s for as long as possible in one ignition cycle without hurting them, but ultimately I’m the one controlling the system, the controller is merely relaying its normal information to me, rather than sitting their computing in silence like a normal bypass essentially does with the controller.

I like your oil switch idea. Though one thing I’d be concerned with is if you were to cycle the glow plugs too much when its warm, or if you spring an oil leak or loose oil pressure or the sensor for some reason. But i guess you probably have a manual override with a normal toggle switch in line with the oil pressure switch as well.

The controller essentially does this with the after-glow cycle but I like your idea. Amazing thing with these trucks is that you can get super creative! Love it!


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[stick_witch]

What is the real purpose of this? I understand switching between manual and auto, but why? Are you trying to disable the GP's if they are not needed?

But, i do like this idea too, you could just simply add a normal bypass, leaving the white wire from the controller hooked up to the solenoid, and then cut it to add an extension to it that runs to a switch on the dash and back to the negative side small post on the solenoid and you essentially have a normal, stock gp system that you can toggle from “auto” to “manual”

The reason I didn’t do this is that with that design I couldn’t have the new reference lights when I wanted to manually control my gp’s without splicing the heck out of the white wire and making a total mess and spending too much time on it. And then the wts light really isn’t a meaningful light on its own to me besides for reference and timing. Really the new, “after-glow cycle” light is the important one I needed which essentially tells you when the controller would originally communicate to the gp solenoid to shut off the gp’s via the white wire. This is quite literally the controller saying “the gp’s have maxed out on run time and temperature and must be turned off to avoid burning them out.”

Thats really the reason I did this, was for that one light, that way I’m not sitting their guessing and counting in my head like an IDIot how long the plugs can/should run. Now I know exactly how long they can run according to the manufacturer. Work smarter, not harder!


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[Black dawg]

Like I told franklin2, every truck is different and every voltmeter instrument is different, my truck when I got it with the old batteries and stock gp’s, wiring, controller, solenoid, everything, ran ~10.8v when the gp’s cycled and didn’t start worth a crap.

Now I run a 130amp 3g alternator, 2 brand new group 65 interstate batteries, new battery terminals and cable, new motorcraft zd9 gp’s, new solenoid, redone gp harness, and all good wiring. Truck starts easy, even when it goes subzero and has been sitting awhile, and gp’s drop to ~11.2v every time when I cycle the gp’s according to my digital voltmeter in my cab coming off the 12v socket. Thats my experience with my truck.

I know guys want to find any reason their system is better than someone elses, but trust me guys, I live in Alaska... my truck doesn’t start EVER without a perfect functioning gp system[emoji23]. My truck drops only to 11.2v because my batteries are brand spankin new, quality batteries that I baby, my charging system is leaps and bounds better than any stock idi, and I don’t let my truck sit around. The only thing there is to debate is whether my voltmeter is more or less accurate, but I’ve tested this with a normal multimeter on the batteries and it says the same thing... so idk, make of it what you guys want...

I’m just here to share my unique “partial” bypass system because I haven’t heard anyone do a write up in it. Or seen anyone do it for that matter.


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Was not questioning your battery voltage numbers at all, or debating anything with you??

Was quoting the post that said battery voltage drops to 8v with glow plugs on. I just walked outside the shop and tested two trucks because I couldnt remember what the voltage was during glow plug cycle, and I tend to not post things unless I know them as fact.

 

[Booyah45828]

Now I see what you're doing. Your plugs are manual, but your using the controller to power lights to give you pointers as to when to turn them on or off. You can run them more or less however you see fit.

Still overcomplicated in my books, but if it's works for you and is how you want it, that's all that matters. Being in alaska, you'll definitely experience the cold more then I would. I like and prefer simple/fail resistant.

*except today apparently, my temps were 23/12, homer alaska was 35/17, so you were warmer today.....

 

[stick_witch]

Was not questioning your battery voltage numbers at all, or debating anything with you??

Was quoting the post that said battery voltage drops to 8v with glow plugs on. I just walked outside the shop and tested two trucks because I couldnt remember what the voltage was during glow plug cycle, and I tend to not post things unless I know them as fact.

Oh yeah I know you weren’t, sorry, i was mostly just referring to franklin’s post. And also referring to my point that all trucks and systems are totally different with regards to what their observed voltage drop will be. Thats determined by a whole number of other things than just if all your glow plugs work properly or not. No one number is right or wrong. His truck probably has different batteries, or older batteries in it, or aren’t fully charged or hes only running one, or his voltmeter is bad, etc. etc. and literally it could have nothing to do with the glow plugs. Heck both you and my voltmeters could be totally bogus and our trucks just magically start with no gp’s, who knows. I’m just stating that its not sound logic to deduce what voltages are right or wrong, or that there is a super specific problem with a super specific part of someones truck just from a difference in observed voltage.[emoji23]
Too many variables.


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[stick_witch]

Now I see what you're doing. Your plugs are manual, but your using the controller to power lights to give you pointers as to when to turn them on or off. You can run them more or less however you see fit.

Still overcomplicated in my books, but if it's works for you and is how you want it, that's all that matters. Being in alaska, you'll definitely experience the cold more then I would. I like and prefer simple/fail resistant.

*except today apparently, my temps were 23/12, homer alaska was 35/17, so you were warmer today.....

To each their own. I just love tinkering lol. I figure if I’m keeping the controller in truck as a glorified $80 solenoid mount I minus well be having it do something for me. Its still fail resistant, just not entirely simple.... although in practice its much simpler than it looks typed up on a forum.

Hahaha yeah, we go back and forth cause we’re by the water. Its been pretty warm this week. Last week it was 0 with blizzards. I also live on the hill so its colder where i live, and then I also haul my sleds out of town to a trailhead to get to my remote cabin every weekend and its usually in the teens or below 0 out there. Truck sits for the weekend too. No help from the block heater out there...


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