'03 Trailblazer Eletrical Issues

Howdy. I'm hoping someone can give me some help with an electrical issue. Vehicle is 2003 LT Extended Trailblazer with the 4.2L engine.

This is my wife's vehicle, so I'm guessing at the extent of the problem. It's been intermittent were the driver's controls for the door locks and windows have not functioned quite right, as well as the interior lighting.

Today I was taking it to the shop to get the front bumper replaced due to someone backing their truck in to it, and I noticed that the rear defrost and rear wiper were not working. I checked the door locks and windows, and they were also dead. Tried to hit the locks from the key fob, and nothing. Front wipers, interior lighting, etc., all seemed to be ok.

When I got to the shop and shut off the vehicle, the door locks all clicked, and interior lights popped on (though the lights might be normal behavior that I hadn't really paid attention to. From that point on, the key fob worked for all the locks except the driver's door. When I started the vehicle back up, the rear wiper was now working. Driver's controls for locks and windows was still non-functioning.

Any ideas at what might be the problem? The shop says it's the control unit on the driver's side needing replaced, but I don't see how that explains the rear wiper and defrost.

Thanks for any leads.

Could be a bad ground or connection in the tailgate, as far as the wiper there is a seperate control module for the rear wiper that could also be an issue.

Ugh. Multiple electrical issues is not something I'm looking forward to tracking down. Faulty ground does make sense, given the intermittence of the issue.

Ugh. Multiple electrical issues is not something I'm looking forward to tracking down. Faulty ground does make sense, given the intermittence of the issue.


A good volt/ohm meter and a good wiring diagram and repair info will help you out.
Good Luck