Where's the Glow Plug Relay?

[BigRedWeather]

Can someone tell me where the glow plug relay is? I don't see it in my manuals. A picture would be great but a good description would be very helpful.


Thanks,


BigRedWeather

 

[95_stroker]

Heres the GPR....

 

[Patrick Feeley]

Your relay is on the front passenger side of the motor, usually under the decorative engine cover. Four wires to it (2 big posts and 2 smaller ones). Did that help? Cheers!

 

[BigRedWeather]

Title

Yes, that did help. It is pretty obvious after you see it. I ran a few tests:

Test 1) Measure the voltage drop accross the glow plug
relay's large terminals while the relay is active. If you get more
than a 0.5V drop (that's what you're measuring), replace the relay.
So I measured the voltage across the large terminals with key out of ignition: 12.79V
Then I measured the voltage across the same terminals after the WTS light was on: 12.54V.
This is less than 0.5 so it says my relay is good.

Test 2) After the truck has been sitting for 2-3 hours and the cylinders are cold and I know it would be hard to start, I turn the key on (the WTS light glows) then, for 20 seconds, I connected the two large terminal on the GPR with a 12 gauge piece of romex. This similated exactly what the relay is supposed to do when it functions properly, I think. But, alas, the truck was still very hard to start. If it had started quickly it would have told me that the GPR was bad. Conclusion: the GPG is not bad.
The glow plugs are probably bad.


Thanks for the help,


BigRedWeather

 

[Patrick Feeley]

Your relay is bad! If the voltage drop (put one test lead on one large terminal and the other test lead on the other large terminal) is more than 0.5V then its bad. You have a DROP of 12.54V meaning that you are getting basically nothing. Cheers!

 

[RoReRi]

Yes, that did help. It is pretty obvious after you see it. I ran a few tests:

Test 1) Measure the voltage drop accross the glow plug
relay's large terminals while the relay is active. If you get more
than a 0.5V drop (that's what you're measuring), replace the relay.
So I measured the voltage across the large terminals with key out of ignition: 12.79V
Then I measured the voltage across the same terminals after the WTS light was on: 12.54V.
This is less than 0.5 so it says my relay is good.

I'm thinking that the voltage drop between the two large terminals with the WTS light ON should be LESS that 0.05 volts dc.
When the WTS light is on, then both large terminals on the relay should be physically the same. With that in mind, the voltage drop between the two “same” terminals should be zero. If there was a resistance between the two terminals (not a good thing) then there would be some voltage measured, any more than 0.5volts dc then you have a bad relay. You say:

Then I measured the voltage across the same terminals after the WTS light was on: 12.54V.
This is less than 0.5 so it says my relay is good.

My vote is that you have a bad relay. And possibly some bad GPs, but I go with the KISS principle. Its so much easier to change the GPR that the GPs. Change the GPR out with one of the stancore (sp?) relays.

Good luck!!

RoReRi

Patrick... seems I'm always about 10 minutes late for 'bout everything...