Just got finished replacing the under valve cover wiring harness and two burnt plugs. Put it back together, started it up, and the glow plug relay started to smoke. I put a test light on the relay and it didn't turn off. Thought I needed a new relay, but the new unit does the same thing. I'm worried that if I run it too long I'll burn up all my new wiring. fficeffice" /> > >
I would think that it’s the glow plug controller, but I read somewhere that the glow plugs in this era Powerstroke are controlled by the PCM. > >
Any ideas? > >
Yes glow plug relay on time is controlled by the PCM. What year truck do you have? On my 97 if I disconnect the small PPL/ORG wire on the relay (it goes to the PCM) then the relay should not activate. The PCM grounds that wire. Look for maybe a short on that wire enroute to the PCM.
__________________ Jim
1997 F250 HD CC 4x4 7.3L - E4OD - 3.55's EVBP Disconnected - Napa 6637 - FPR Shim 3" Down Pipe & CD - 302 Stat - 159 K Miles
The only thing I pull is the extension cord to my truck.
This is a '95 F-350. The smaller wires on the relay are both red, go into a plug, and come out (1) pink and (1) red (with green stripe) on the other side of the plug. The wires quickly disappear into the covered wire harness.
Where is the PCM? Is it the silver metal box under the hood near the fuse box on the drivers side? Or is it under the dash where you plug in a code reader?
This is a '95 F-350. The smaller wires on the relay are both red, go into a plug, and come out (1) pink and (1) red (with green stripe) on the other side of the plug. The wires quickly disappear into the covered wire harness.
Where is the PCM? Is it the silver metal box under the hood near the fuse box on the drivers side? Or is it under the dash where you plug in a code reader?
The Red(with green stripe) is the +12 volts (always hot) and the other is the wire going to the PCM. Check where the harness(s) goes across the drive side valve cover for rub through and possible damage.
PCM is located in the area you mentioned but so is the IDM. I don't have a picture of it but somebody will probably post one.
You should have +12 volts on both your smaller Red wires on the Glow Plug Relay for the relay to be OFF. To be ON one of the Red wires will be at ground (via the PCM).
__________________ Jim
1997 F250 HD CC 4x4 7.3L - E4OD - 3.55's EVBP Disconnected - Napa 6637 - FPR Shim 3" Down Pipe & CD - 302 Stat - 159 K Miles
The only thing I pull is the extension cord to my truck.
For what its worth, I replaced it with the same relay that has been on the rig. I'd say its not grounded through the base. The metal base is riveted to the plastic case of the relay. I checked to be sure by touching the base to the neg battery post and put the test light on the pos battery post, then touched the tester to all the posts on the relay - didn't light the tester, didn't complete a circuit... not grounded through base.
I turn the key on. One of the small posts has 12+ volts. The other has .5 volts. (Doesn't turn a test light on). By what you said, that indicates relay is on. I didn't see any obious signs of wear on the wire harness across the valve cover.
I'm stumped.
1997 F-350 PSD Auto 257K
Tuned by Tony, Built by ME!
TDP/TW tunes
AD injectors
6.0 IC
17* HPOP
Tru-cool
The Cure
ESE Eliminator
6" stacks
4 Wh disc brakes
1/4 mile-14.59@88 MPH
Click the Picture for wiring diagrams, tech info and Pictures!
TJBEGGS- I guess I was over worried! I timed it and the GPR shut off @ 65 seconds. The relay on my '92 cycles so fast that I was worried about burning up wiring on the '95. Sorry for all the commotion about nothing - thanks for the advice!
ffice" /> 
