GLOW Problems

[nate_o23]

I just bought an 85 Sub. I got it cheap b/c it would not start. The guy put a new GP controler on it but that didn't help. I have replaced all the GPs but still nothing. The wait light will not even come on. There is 12V at the one big wire and 12V at pin D on the plug, but no cycling or clicking sound. Is the controler bad?

[jackrabbit]

There is a temperature inhibit switch that is at the back of the engine sensing the water temperature. It doesn't allow the GP controller to come on when the engine is warm.

If either the terminals get corroded on the plug going into it, or the switch is bad, your controller won't cycle.

Try cleaning those off those terminals or jumper accross the plug to see if that works. It is located on the passenger side at the back of the engine on my truck, I would expect it to be in the same place on yours. I carry a small jumper wire in my truck for just this propose.

[BobND]

[QUOTE]Originally posted by jackrabbit:
[QB] There is a temperature inhibit switch that is at the back of the engine sensing the water temperature.[QUOTE]

Good poin, about that switch. It is NOT even needed with the newer glow plugs. Simply jumper the wires at the 2-terminal connector, and leave the switch out of the circuit. You'll get better "warm" starts.

[nate_o23]

THANKS! I found the switch, put in a jumper wire and the glow plugs cycled! The truck starts fine now.

[Robyn]

Nate
Change the switch out for a new one when you get a few minutes. Having the glow plug inhibit switch working is a good thing as it saves your glow plugs from being used on a warm engine.
My 86 did the same thing once and had to fix it on the road in the snow in front of a motel, :0(

[BobND]

Robyn, Why don't you want your glow plugs to cycle on a warm engine, giving a quicker start, and cleaner exhaust at startup? With 60G's or other various glow plugs available today, there's no harm in it, and the quicker, cleaner starting is nice.