Glow Plugs not working all the time and Parking Brake light on while cranking

[mill5471]

As said, my glow plugs only seem to work when they want to on my 85'. Also the same time they quit being reliable i noticed the parking brake light comes on while cranking the engine over. Also, when they do work they very rarely will come on after the truck is started, which they used to always come on after it fires up. Several people have told me that i have a bad ground somewhere. I have cleaned both ends of the neg. battery cables and have yet to do the other grounds.

My question is am i on the right track and is there a ground somewhere in the dash and where is it?

I have done some researching on here and i have checked the main plug on top of the gp controller and that seems to be fine and tight. I also am suspecting the temp sensor to be getting stuck in the "hot" position, not allowing the gp's to come, but the parking brake light i believe is a ground problem. Any tips or advice is appreciated, Thanks

 

[mill5471]

I cleaned the grounds under the hood and found the problem with the ground from the gp controller to the intake stud. So far after 2 days the gp's seem to be working back to normal and cycling normal.

The problem is the brake light still comes on while i'm cranking the engine over.
Anybody have any ideas?