QuestionI recently bought an 86 with 104K and a plow for $2,000! I'm here in the NE and it's 16 degrees today.
I was told the plugs were shot, replaced all 8 before I tested the electical. I'm not getting any power to the plugs. At the relay I have 24 volts on the top, 5 and 5 at the smaller middle ones and 0 on the bottom! I have tested every other conection/ both ends of fuseable links all fuses. At controller I get 5 volts in(black wire) I tried to do my homework first, Any thoughts Thank you
AnswerHi Mike,
Actually, that thing under the hood that looks like an old solenoid, is a relay.
The actual controller for the glow plugs is up above the brake pedal, either hanging, or zip tied to some other wires.
It is in a plastic enclosure about an inch thick, by about two and a half inches wide, and about four inches long.
The large end comes off if it is on there, and the board can be pulled out.
There is a resistor that burns out, or the connections can be loose or corroded.
It is also possible the fuse in the regular fuse block is blown.
memphisequipment.com is a place to get parts for them.
You can use starting fluid, as long as you are sure none of the glow plugs are hot, so I just disconnect the double orange wires, which are the ones to the plugs.
That other one that has power all the time, should come from a big resistor on the firewall, and although it shows 24 volt, it drops to 12 when under load.
If it is connected directly to the 24 volt strip on the right side of the firewall, that explains why your system doesn't work. Those are 12 volt glow plugs.
A little side note for you. Almost 100% of that truck is stock Chevy 12 Volt. The ONLY 24 volt item is the starter and solenoid. Even the alternators are 12 Volt, 100 amp, isolated ground alternators.
Van
