Ok 1st gen'ers. Here's the problem. With engine idling a/c or heat either one on with the blower motor on high the electrical will shut down completely. After a few seconds I hear a click behind the dash and the electrical will come back. It also has done this with the blower in the medium setting and the low setting. I have replaced the blower motor, ignition switch and the fan switch. Now it only does it when the fan switch is in the high position.
Has anyone experienced anything like this and if so what was the problem? As I said the electrical on the entire truck shuts down for a few seconds when this happens. Once I hear the click behind the dash I can restart the truck. Any help will be appreciated.

 

Does it sound like a relay or solenoid or could it be a spark? It could be a loose ground under the dash and it's sparking. Is it an IC or non-ic truck?...Mark

 

It's more of a metallic click like a relay or solenoid would make and it is IC.
Thanks for replying

 

I don't know much about the IC trucks with the pcm and all. Hopefully an eletrical guru will sign in, good luck...Mark

 

Thanks

 

I'm willing to bet it's either an oxidized battery terminal or an internal fault in the battery.

I've seen oxidized terminals do some strange semiconductor things many times. I'm not talking about the white corruption that happens on the outside, but the black layer that sometimes forms between the connector and the post.

 

Thanks, I will check that out. My positive battery cable is a little worse for wear as well. I suppose that could be adding to the problem?

 

Well I cleaned the terminals and even tried a different battery I had but, still have the same issue. Is it possible it could be anything to do with the fuse links. Any other ideas I'm willing to try.

 

It wouldn't hurt to check them and all the ground points. Do you have a volt meter? See here for good info on the fusible links...Mark

 

That's what I was thinking, sounds like someone may have put a self-resetting circuit breaker in there somewhere.
Isn't there a relay on the intercooled trucks? Could it be going bad? Just an idea.
Is the click under the dash or out under the hod?

 

At first I thought it was behind the dash but, while I was messing with it earlier it seems to be under the hood between the brake booster and the grid heater relays or this general vicinity

 

maybe a fuse link sparking or almost apart ? Or there is also a relay/ ??? on the fire wall behind the glove box check that also 2 --5/16 screw's pull it out

 

When you hear the click, is the ignition key in the on position? If so, could be the shutdown relay, which is on the left fender (one of the 3 there) Also, what all fails? Does it crank and not fire? Does it not crank? Radio, heater, headlights, turn signals, etc. etc.

This isn't a real complicated system. With a little detailed information, such as exactly what you observe under exactly what circumstances. With several such observations under even slightly different circumstances, we should be able to figure out where to look for the trouble.

You do need a multimeter, or a large bank account to throw parts at it. Your choice.

 

When it shuts down with the switch on there are no power windows, no blower, no power to ignition. I haven't noticed anything else. When it does this I will turn the switch off and in a few seconds click and everything is back

 

Might be a bad ignition switch...Mark