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The Mother Of All Electrical Problems

snsime

By snsime
in Ask A GM Technician

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snsime Enthusiast

snsime

Posted
Posted

I would be amazed if anyone can offer any advice on this... but we're so beside ourselves we're looking everywhere we can to try and glean some help.

 

Bought a 02 Suburban LT 5.3l not that long ago from a (reputable) used car dealer.

 

Even when we were test driving it, once in a while I'd hear a clunk from the back of the truck. Discovered a few days after we got it home that it was the rear wiper arm "jumping" in it's cradle. It would do it (intermittently) when we'd lock or unlock doors, step on the brakes, honk the horn, put the truck in gear or put on turn signals. I didn't think it was a huge deal at first.

 

Then sometimes the wiper started to give a wipe, out of the blue, or when activating any of the above, then go back to it's cradle (jumping still existed). This was begininning to seem pretty strange.

 

It got to the point where the wiper would start coming on for extended periods of time, particularly when putting it in gear or activating turn signals. It would stop when putting truck in park or turning off turn signals. Now I'm concerned.

 

Then it went nuts this week. Wiper stays on all the time now when in gear. In park, it won't wipe, BUT, it will turn on when I put either of the turn signals on, step on the brakes, or activate locks. The turn signals have started blinking very rapidly all the time, and will dimly light the opposite side signal as well. Horn has stopped working, but the wiper will wipe when ever "honked" (in park). And the fog lights no longer work either (they certainly did before). I've pulled the wiper fuse from the underhood panel, but the rapid turn signals and all the other problems remain. Strangley, when I was towing our camper trailer this week, with the 7-pin plugged in, the turn signals worked normaly (all other problems remained). As soon as I unhooked the trailer, they stopped working properly again.

 

This dealer looked at it for two days and couldn't seem to find the problem. It's going back again next week, and they say it will have to go to a specialist.... but they don't seem very optimistic that a bizarre problem like this will be easily corrected.

 

Sigh. Any insight or advice prior to me spending countless amounts of money I can't afford to spend for someone to try and root through miles of wire - would be most appreciated.

 

Thanks

bobcat5544 Enthusiast

bobcat5544

Posted
Posted

With out seeing the vehicle for myself most logical cause would be a bad ground at G203 located at the upper left of the I/P or the body control module.

snsime Enthusiast

snsime

Posted
  • Author
Posted

Thanks very much for the response!

 

Truck goes in Tuesday Aug 14th, I'll update this thread with progress or (cross fingers) solution.

snsime Enthusiast

snsime

Posted
  • Author
Posted

FIXED! :cheers:

 

Thanks to the advice here, the techs there checked first for grounds (this feedback was very valuable, particularily because when I told them a GM-Tech has suggested checking grounds, they virtually dismmised it, insisting that that was a parasitic power source or something).

 

Turns out the ground to the back of the engine block, or one of them, left side I think, was hanging by a thread.

 

Everything works exactly like it should now.

 

Thanks again!

 

-Scott

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