Chattering glow plug relay

[FMJ]

Ok, so I've been having an intermittent glow plug relay chattering problem. My 86 1009 would start normally, glow plug system functioning normally when cold, however, after the engine is warm with a brief shutdown/restart, the glow plug relay either would not function or would chatter for 30-60 seconds after starting, energizing the glow plugs, with a warm motor running. So I started troubleshooting the GP system, everything checked out but still the problem persisted. I went back to the schematics in the TM and focused on the GP temp switch/wiring. I found the insulation between the black and yellow wires at the plug was gone/deteriorated allowing the 2 wires to make intermittent contact and making the GP controller card cycle the GP relay rapidly. I repaired the insulation between the 2 wires on the temp sensor plug and my "chattering GP relay after a warm start" was gone. I'll post a pic of the plug/wiring tomorrow. Note, this is the plug on the drivers side at the rear of the motor next to the vac pump.

Ed

 

[FMJ]

Pics:

 

[FMJ]

I've checked 2 of my trucks, and both had the same issue with the insulation breaking down and the wires touching each other.