Glow Plug Bypass - not working

RSchanz

Full Access Member
Joined
Sep 29, 2020
Posts
299
Reaction score
93
Location
Petaluma, CA
Went to start the truck today and it wouldn't turn over. I noticed that my glow plug light wasn't turning on so I started checking around with my icepick. Wire on the left of the switch was live and the wire on the right coming out of it was not lighting up. I pressed the button while trying and nothing changed.

I did notice an area on the wire where the insulation was worn off and looked sketchy so I'm thinking of replacing the wire regardless and at a minimum putting electrical tape over it.
You must be registered for see images attach


I'm not sure what the wire attaches to but I've uploaded a picture. Can someone tell me what it is? The wire was also not appearing to be live at this spot either. This leads me to believe the button is likely not working.

You must be registered for see images attach


I'm assuming it's some kind of relay with power going in on the left and when I push the button it sends power out through the wire on the right.

You must be registered for see images attach


Any guidance would be appreciated!
 

IDIBRONCO

IDIBRONCO
Joined
Feb 5, 2010
Posts
12,235
Reaction score
10,925
Location
edmond, ks
That is the glow plug relay on the 6.9 style glow plug set up. If your button doesn't work, then your glow plugs won't work since this activates them. Originally, the controller activates this relay, but people like to bypass them with a manual set up since the controllers have a habit of failing. Often it's in the "on" position which burns out your glow plugs.
Now if your starter isn't working, it's probably not related to this relay or the button. Although there may be a fuse or fusible link that's been burned out due to the short. I ALWAYS install an inline fuse right off of the power source for manual controls. Since there's two wires in your picture, this button appears to be powered from an under hood source like the starter solenoid that's located on the passenger's fender right behind the battery.
 

RSchanz

Full Access Member
Joined
Sep 29, 2020
Posts
299
Reaction score
93
Location
Petaluma, CA
That is the glow plug relay on the 6.9 style glow plug set up. If your button doesn't work, then your glow plugs won't work since this activates them. Originally, the controller activates this relay, but people like to bypass them with a manual set up since the controllers have a habit of failing. Often it's in the "on" position which burns out your glow plugs.
Now if your starter isn't working, it's probably not related to this relay or the button. Although there may be a fuse or fusible link that's been burned out due to the short. I ALWAYS install an inline fuse right off of the power source for manual controls. Since there's two wires in your picture, this button appears to be powered from an under hood source like the starter solenoid that's located on the passenger's fender right behind the battery.


Thanks for the reply. I'm aware of the issue with the factory glow plug set up. I didn't install this set up so I'm starting to work on figuring out how it goes haha.

It's definitely linked to the starter solenoid for power. I mentioned that the wire going into the button on the left is live where the wire going out of the button on the right isn't live. This is the case whether I push the button down or not. It leads me to believe that there might be an issue within the button.
 

Selahdoor

How can I help you, or make you laugh, today?
Supporting Member
Joined
Oct 26, 2015
Posts
2,253
Reaction score
2,004
Location
Index Wa
Thanks for the reply. I'm aware of the issue with the factory glow plug set up. I didn't install this set up so I'm starting to work on figuring out how it goes haha.

It's definitely linked to the starter solenoid for power. I mentioned that the wire going into the button on the left is live where the wire going out of the button on the right isn't live. This is the case whether I push the button down or not. It leads me to believe that there might be an issue within the button.
Yep. Replace the button switch.
 

IDIBRONCO

IDIBRONCO
Joined
Feb 5, 2010
Posts
12,235
Reaction score
10,925
Location
edmond, ks
There's plenty of them on either Ebay or Amazon. Just type "starter push button" into the search bar. Since your button is powered from the starter solenoid, I'd recommend installing an inline fuse just in case the insulation gets rubbed off the wiring again. The most you would need is a 10 amp fuse. A 5 amp would probably do the trick as well. All you're doing is using a manual on switch for the relay. It doesn't take a lot of power to do that.
 

RSchanz

Full Access Member
Joined
Sep 29, 2020
Posts
299
Reaction score
93
Location
Petaluma, CA
Good call, thanks for the recommendation.

This may sound stupid but this is the first vehicle I've owned with two batteries. Is there a certain order in which I should disconnect the batteries?
 

Selahdoor

How can I help you, or make you laugh, today?
Supporting Member
Joined
Oct 26, 2015
Posts
2,253
Reaction score
2,004
Location
Index Wa
Good call, thanks for the recommendation.

This may sound stupid but this is the first vehicle I've owned with two batteries. Is there a certain order in which I should disconnect the batteries?
Disconnect negative on driver's side battery first.

Then negative on passenger side.

Then both positives.
 

IDIBRONCO

IDIBRONCO
Joined
Feb 5, 2010
Posts
12,235
Reaction score
10,925
Location
edmond, ks
Disconnect negative on driver's side battery first.

Then negative on passenger side.

Then both positives.
This is probably the proper way to disconnect them. I honestly have no idea on the order I disconnect them. I also only disconnect all four cable ends when I'm removing the batteries. If I'm doing any type of work and need to disconnect the batteries, I'll disconnect the passenger's side negative and the driver's side positive. I do this because sometimes the driver's side negative has a tendency to fall down behind the battery and be difficult to find sometimes. As for the driver's side, to me it's easier to leave the double positive hooked to the battery. The battery is just as disconnected whether you leave the positive or the negative hooked up. Sure, you can get an arc off of the passenger's side positive this way, but I just wrap a rag or something similar around the end. You can zip tie the rag on or even wrap it in electrical tape to help hole it over the cable end.
 

RSchanz

Full Access Member
Joined
Sep 29, 2020
Posts
299
Reaction score
93
Location
Petaluma, CA
Any idea how or if this button should be grounded? Somehow it seems a little sketchy
 

Selahdoor

How can I help you, or make you laugh, today?
Supporting Member
Joined
Oct 26, 2015
Posts
2,253
Reaction score
2,004
Location
Index Wa
Any idea how or if this button should be grounded? Somehow it seems a little sketchy
Maybe I don't really understand this question, but...

If the button is switching power... (In other words, power comes from some source such as the fuse block, or the ignition switch... Then goes to the button... Then from the button to the solenoid...), then there is no ground involved. Ground one side of that, and you'll have major problems up to and including maybe a fire.

If a wire comes from the solenoid, to the button, then from there, to a ground, and no power source is involved otherwise, then the question is moot, because ground is a part of the circuit.
 

IDIBRONCO

IDIBRONCO
Joined
Feb 5, 2010
Posts
12,235
Reaction score
10,925
Location
edmond, ks
Maybe I don't really understand this question, but...

If the button is switching power... (In other words, power comes from some source such as the fuse block, or the ignition switch... Then goes to the button... Then from the button to the solenoid...), then there is no ground involved. Ground one side of that, and you'll have major problems up to and including maybe a fire.

If a wire comes from the solenoid, to the button, then from there, to a ground, and no power source is involved otherwise, then the question is moot, because ground is a part of the circuit.
Exactly. Basically, power to switch. Then power to relay. The solenoid isn't required to heat up the 6.9 style glow plugs manually. In fact, you don't want the solenoid plugged in to the wiring harness since it could/would still send power somewhere. If it was stuck "on", then it may drain your batteries over time. When I put the 7.3 in my Blue Truck, I didn't even bother putting a 6.9 controller in the head. There's already a plug here, so it's not going to leak coolant.
 

RSchanz

Full Access Member
Joined
Sep 29, 2020
Posts
299
Reaction score
93
Location
Petaluma, CA
Maybe I don't really understand this question, but...

If the button is switching power... (In other words, power comes from some source such as the fuse block, or the ignition switch... Then goes to the button... Then from the button to the solenoid...), then there is no ground involved. Ground one side of that, and you'll have major problems up to and including maybe a fire.

If a wire comes from the solenoid, to the button, then from there, to a ground, and no power source is involved otherwise, then the question is moot, because ground is a part of the circuit.

I get ya. Learning more about electricity and wiring with each project vehicle.

Exactly. Basically, power to switch. Then power to relay. The solenoid isn't required to heat up the 6.9 style glow plugs manually. In fact, you don't want the solenoid plugged in to the wiring harness since it could/would still send power somewhere. If it was stuck "on", then it may drain your batteries over time. When I put the 7.3 in my Blue Truck, I didn't even bother putting a 6.9 controller in the head. There's already a plug here, so it's not going to leak coolant.

Whats the alternative option for powering the glow plug harness besides using the solenoid?
 
Top