OK< I got gremlins in here....replaced the glow plug relay and the darn things wouldn't cut off...so I had to disconnect the relay. Turns out the one I bought grounded through the baseplate, so it stayed energized. It also had the ability to keep the truck running after turning off the key, necessitating pulling the ECM fuse.

Got the right relay, but it won't energize. Jump the poles, and the glow plugs "glow" and truck starts fine. I'm ready to just run a wire through and put a switch on it, to ground the relay manually.

Did the first "right" relay fry something? What controls the ground for the relay? I'm not angry, just terribly, terribly hurt.......

 

One of the little posts carries a ground signal from the PCM when the key is turned on. Have you tried disconnecting the batteries for a while to let the PCM reset in case it quit sending a ground signal due to the grounding issue from the first relay?

By the way, how did you find out the GP's were staying hot with the other relay?

 

I did the mod with installing a small LED light. Started the truck and the light stayed on....gave it a few seconds of running, turned the key off and it kept running. Jumped out and quick pulled the GP wire off the relay.

 

Smart move. That LED probably saved you a set of glow plugs.

 

Yeppers...just went out and did some troubleshooting...not getting a ground thru the orange wire off the relay, but relay works if I manually ground it....I'm wondering if something fried from the wrong relay. I'll probably just run a wire inside and install a push button to ground, and it's starting to warm up.