Glow Plugs don't work

[Dave T]

I have a '91 F350, with a non-turbo 7.3L diesel. When I try to start it the glow plugs skip thru the wait to start cycle [warm up] and go to the on off cycle. I have installed a new relay/controller and new glow plugs. The GP harness checked out good. Any ideas?

[Broncoguy]

My 92 has a sensor in the driver side head toward the front. From my understanding it basically tells the controller that the engine is cold and the glow plugs need to cycle. My truck was doing the same thing after an engine replacement and I noticed that I had broken the stud off the top of that sensor. I replaced it and it worked great until the glow plug controller went out again...

Now the solid state part of the controller is bypassed with a switch, hold the button, count to 10 and she fires every time.

[jweaver]

Wow I just put a new controller/ relay on this morning. The WTS light blinks once and the plugs dont warm, I am also getting a click from the relay at 5 second intervals when the key is on.

[trailbuilder]

I will check on my 91 if the sensor is bad or broken...that would be nice instead of the $220 Glow Plug Controller. Mine clicks and does not heat the glow plugs.