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Glow plug relay *POPS*...but glow plugs don't light?

6K views 15 replies 10 participants last post by  roadhog0 
#1 ·
I'm not too worried about the glow plug relay, since it's a relatively cheap fix, but from a conceptual view...

My '82 has push-button glow plug activation. Recently, I'd bend down to press the glow plug light, hear the relay *POP* (or *THONK*, *PANG*, whatever sound effect you want to use) but the "glow plug" light on the dash wouldn't illuminate for a couple of seconds. Then, the light would show and the truck would start.

This past week after being out of town, I hit the push-button, hear the *POP* and NO "glow plug" dashlight...plus, the truck would turn over but not start. :(

Tonight, after seeing the thread on using jumper cables to bypass the relay, the "glow plug" light immediately came on and the truck fired off triumphantly.

MY QUESTION IS...why would I hear that heavy-duty *POP* without the glow plug relay working? Does the jumper cable trick bypass the relay, or my manual push-button switch? Is a new glow plug relay needed?
 
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#2 ·
Internal wear on the relay contact disc and/or bolts. Fairly common on the '82 system. Replace the #560580 relay.
 
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#3 ·
The relay is activating but the internals are burned up or corroded and are not making a good connection so it won't feed the power to the glow plugs like it should. If you change the relay you will be good to go
 
#4 ·
My relay went haywire too. It had intermittent varying voltage going out of it.
The noise is confusing -think it sounds like it's working -but inside its burnt out.
 
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#6 ·
Yup, with a test light.

Check for power in, then check for power out when you push the over ride button.

I'll bet the relay is done ....
 
#8 ·
"Brand new" does not mean it's good. Parts have been known to be bad out of the box.
You have to test it.
 
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#10 ·
Yup....

Full manual over ride, 60g glow plugs ... go forth and diesel on ...
 
#12 ·
I figured you would say that. I gotta figure that out. The write-ups are good. but with mine being an 82, some things are a bit different. plus I am still trying to figure exactly what the past owners have done.
 
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#13 ·
Actually 82 is the easyist. Those with the solenoid on side fender. You run power to a push button switch, and from the other side you run it to the solenoid. Just disconnect the spade plugs, one side will come from the switch, the other is a ground.

Doing an override on the other styles reguires running battery power to solenoid, then another to existing relay, plus the push button wiring-harder to get lengths right first time too.

Sent from my SM-S920L using Tapatalk
 
#16 ·
Your switch will also last longer if you trigger on ground side. If possible you always want to switch ground.
 
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