Glow plug relay

[Gone Huntin']

I'm working on my neighbors '92 F250 7.3 IDI. As I understand it, the white wire at the relay supplies ground to activate the relay, is this correct? The glow plugs haven't been working on this truck since he bought it. I checked for voltages at the relay and got 12v where the big yellow wires are, 12v w/key on at the front small terminal w/red wires, no voltage at the terminal with the resistor, and nothing (ground or power) at the white wire. I supplied ground to the terminal with the white wire and the relay still doesn't work, however, if I ground the base of the relay it works, but won't disengage until the key is off. I'm thinking it has the wrong relay on it, or a bad relay or both. If it is a bad relay, what relay should I use to replace it? I don't want to replace the controller. One more thing, all of the pictures I've seen on here of the controller/relay have the small terminal wires reversed, the white is where the red is in the pics and vice versa. Does that matter?

 

[mech140]

it did on mine . go to the archives and look for articles from mel he has got the moose trucks....hope this helps

 

[Gone Huntin']

I read the articles before I posted. This is what I was talking about. This is how his is wired.

 

[mech140]

there should be two letters on top of the relay,one is an I is where the white wire goes and an S is where the red wire mounts. your wire placement will make a differece.

 

[Gone Huntin']

Thanks, I guess I just need to get a new relay. Should I just get one for a 6.9 style to put on there?

 

[mech140]

its the same relay if you still have problems you can always by pass the gpr controller.....

 

[Gone Huntin']

I think I'm gonna do that anyway, I'm not getting a ground signal from the white wire and I should, right? I've already checked the glow plugs with a test light.

 

[Compu Doc]

Have you checked the glow plugs with an ohm meter?. I had 3 bad glow plugs which was causing hard starts in winter without plugging the truck in and causing the relay to click really fast. If you have bad glow plugs I don't know how many but I am sure a certain number over three might cause the relay to not work at all.