Manual Glow Plug Switch Issues

[TrueBurner]

Hey All

When I purchased my truck it came with a manual glow plug switch previously installed but it has constantly given me trouble. I have removed and cleaned off all connections and replaced a couple terminal rings that were worn. Even put in a new breaker. It tends to work for several weeks then something happens again. Right now you can hear the switch "click" when engaging but the voltage on the dash doesn't drop. I have to crank the engine for 15-20 seconds then flip the switch and the voltage drops. I am not super familiar with these systems so not sure how to trouble shoot further, if it's a faulty switch or harness or battery or glow plugs or what. Was told when I got the truck a little over a year ago that the harness and plugs had been replaced recently with oem. Was thinking at this point to just start over with a dialed in classic diesel design conversion kit since I know how top notch the quality is. Unless I am missing an easy fix. Thanks again!

 

[TrueBurner]

Just as an update, truck has been sitting for a day and now the voltage on dash doesn't even change after cranking it. Switch still "clicks" but doesn't do anything. Batteries are only a year and a half old, Duralast Golds if that means anything. Weather has only been in the high 40s-50s.

 

[franklin2]

You are going to have to get a meter or testlight if you want to determine what is wrong. It could possibly be the solenoid in the controller, but you would have to get a tester to verify that. It's basically a solenoid like the starter solenoid on the fender, but it's job is to send 12v to the glowplugs when the switch tells it to.

P.S. Yes, if it's converted normally like most are, the controller is still partially used, it's just the brains of the controller are not used anymore.

 

[IDIBRONCO]

I was thinking that it's something with the controller too. I think that the "crank it over and then it works" was just a coincidence. The guy I got my first 85 F250 from claimed the same thing about it.

 

[Black dawg]

Sounds like the relay contacts are in bad shape, and not flowing current to the glow plugs. With someone holding the button check for power at both big posts of the relay. Probably just engine vibration that makes it work after cranking.

 

[Cheesy]

I’m also having a very similar problem. I recently switched to the manual push button controller. And my glow plugs are completely dead. My controller clicks on and off by the button but it doesn’t hear my plugs at all. Brand new harness and glow plugs. I tested to see if I was getting power. I put my black wire on the battery ground post and red in the harness. What was interesting was without the button it was reading 11 bolts and change. Then with the button depressed the harness read 12 bolts and change. My dash battery indicator also doesn’t drop when I push the button any clue. Do I need a new relay? Also should the squiggly peice of metal be hot to the touch after a few seconds?

 

[Cheesy]

Just a note I figured out my problem. My sylinoid got stuck open and burned out all my glow plugs. I did the ohms test on em and nothing came up And I had the 11.5 bolts at the harness right when I turned the key on without pushing my button. So 140$ later I have a new solinoid and 8 new glow plugs. Gunna put em on tomorrow and hopefully my truck will start like it should

 

[Stu Bailey]

That sucks man, sorry to hear about that. Were they easy to get out after burning up? I may be wrong but I believe with a properly wired manual push button you shouldn’t have the problem again. Even if the solenoid was stuck open your push button should break the circuit. So there’s a light at the end of the tunnel??

 

[Justin Bramucci]

Hi, I'm new to this kind of stuff. My son has an 1984 F250 6.9 and is having glow plug issues. Had a guy put in a manual switch and new relay. It worked for a little bit but now the glow plugs have constant power and when the button is pushed it kills the power to the plugs. I've tried to find a good wiring diagram to see if it is wired correctly but can't seem to find one. Any help is much appreciated. Thank you

 

[IDIBRONCO]

Hi, I'm new to this kind of stuff. My son has an 1984 F250 6.9 and is having glow plug issues. Had a guy put in a manual switch and new relay. It worked for a little bit but now the glow plugs have constant power and when the button is pushed it kills the power to the plugs. I've tried to find a good wiring diagram to see if it is wired correctly but can't seem to find one. Any help is much appreciated. Thank you

If the glow plug system is still original, it's pretty easy. First, unplug the controller and leave it off. Next, there's a relay on the passenger's side fender that's sitting horizontally. It looks like the fender mounted starter solenoid. That's what activates the glow plugs. There is a purple wire that attaches to one small terminal. Just use your manual control to send power to that terminal. Now you have manual control for your 6.9 style glow plugs.

 

[Justin Bramucci]

I don't think it is original. When I first got the truck I replaced the controller thinking that may fix my problem but no luck. I have since unplugged the controller. The guy ran the manual switch from the battery to button inside the cab then to the relay on the fender with a inline fuse.

 

[IDIBRONCO]

That sounds like it should work fine then.

 

[Rdnck84_03]

With that setup and the fact it is always hot unless the button is pushed makes me think the button itself is bad.

Do they shut off when the wire to switch from the battery is unhooked? If so I would replace the switch first.

James

 

[franklin2]

Those solenoids, no matter if it's the glowplug solenoid (relay) or the starter relay, they draw more current to activate them than you think. And when you release the button, the coil in the solenoid (relay) will send a high voltage backward EMF backward through the wiring and this will cause a spark at the switch.

So in other words, when you get a pushbutton for your glowplugs, get a good one that can handle some power through it. I bought this at Autozone and have been using it on mine for years and years. It can handle 20 amps through the switch itself, so it's a beefy switch.

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[rhkcommander]

Maybe I'm crazy, but I believe I wired my relay unorthodoxly:

Big hot post tied to the S post (switch/signal, it's what the controller would power), and ran a wire from the small ground post to a grounded switch in the cab. This WONT work for relays that don't have a small ground post (internally grounded), but my logic was that if the wire was ever damaged at worst I'll cook my GPS, and I don't have to run an extra wire for hot runs like you would toggling the S-post. Been fine for many years on an antivandal push button.