So this work truck we have has been mickey moused by the previous owner.

The black connector in the wiring harness going towards the fuse box had been melted on one side where the power wires for the glow plug controller go. These melted wires had been bypassed and instead of simply bypassing the connector they bypassed the fuse box as well and wired directly to the front of the fuse box where the main power wire is. Not sure why these wires would have melted the connector in the first place? Suspected that power to the plugs was not shutting off. Also think that the glow plugs were improperly set up to be manual as there is a switch in the dash and a wire running to nowhere currently.

Before we started going through everything there was no power to the glow plugs at all, no wait to start light would come on, no solenoid clicking, so we replaced the solenoid and controller. After doing this everything worked, but we would get smoke from the wire connection bypassing the connector where they connected to the front of the fuse box, where the main power wire is. While doing this had ordered some motorcraft glow plugs and stopped and waited for those to come it. Thought maybe there was too much resistance and that was causing the heat, thought maybe that was the original problem as well.

Today I replaced all the glow plugs, 6 of them were burnt real badly. Turned the key and everything worked and fired up fine, except now the busbar on the controller is getting red hot, and thinking back did not actually hear the solenoid turn off when the wait to start light turned off.

So back to my suspicions that for some reason power to the plugs is not being turned off. Everything is basically brand new, and before the last owners mickey moused the wiring there was obviously a problem which led the them doing what they did.

Any advice for things to look for?

 

Uh... Unhook one of the small wires on the controller solenoid. It should /not/ heat up/glow plugs should not work.
If it does, chances are the controller solenoid is shot and stuck on.
It stops heating up, replace the entire controller.

 

Will try unooking one of the small wires and see what happens. Entire controller though, or just the solenoid? Just replaced everything, these controllers aren't cheap. If that is the case that I have to replace it all again, will just make it manual.

 

it sounds like you have wires hooked up wrong enabling the controller to keep the relay engaged.