I bought my 2005 blazer ZR2 with a wiring problem. The rear passenger break, signal, tail lights and the power lock on the tail gate would not work. Which is weird because most of those are on different circuits. So I replaced a few things and nothing did the trick. I used a multimeter and did a few tests and concluded that there was a break in the wire somewhere after the fuse box. I noticed under the floor mat there was a hole in the carpet where the previous owner would have rested the heel of his foot while it was on the gas or break. After tracing the wiring harness I saw it ran in a line in the middle of the floor matt (right by the hole in the carpet), under the drivers seat and to the back. I ripped out the carpet under the drivers side floor matt to discover that water had gotten in through the hole and into the wiring harness. This combined with the previous owners foot moving the harness back and forth while driving created many splits in the wires and even started a small fire that was not even noticeable unless I ripped up the carpet. I have included pictures of what this had looked like before I fixed it. I thought I could share this story to hopefully save someone and expensive repair at a mechanic when all you need to spend is about 20 bucks to fix it. have a good day!

The repair:
I cut the burnt wires out a soldered new wires in and re taped the harness with electrical tape. Before I put the harness back in it’s place I glued strips of cut up rubber yoga mat under where the harness sits. I just did this yesterday everything works I will have to wait a few year to see if this stoped the problem from creating itself again.

This is what it looked like after I sorted out the wires about 7 of them were completely not working some were just hanging on by a thread lots were somehow untouched

 

Nice work. I helped another member a while back and we ended up in this exact spot. Must be the windshield or door seal leaking.

George

 

Yeah, I always thought that was the dumbest place ever to put a wiring harness. What were they thinking?

 

Thanks for sharing.

I had a similar wild-goose chase this summer. I thought my electronic door lock was bad on the driver's door. I replaced it (which was a bear to do) only to have it still not work. I then found that the dome light was staying on and the security system wasn't working.

I found myself looking all through my wiring diagrams in the service manual and tracing wires all the way back to the lift gate! But nothing worked.

I then realized that the reason the dome light was on was because with the door panel off, the door switch was not being depressed. And the reason the security system wasn't working correctly was because I had disconnected part of its circuit that resides on the underside dash cover.

Finally I found that it was a single broken wire in the door jam that had been responsible for the door lock not working and that replacing it was not necessary at all!

I suspect that this wire was broken because someone hacked into the harness there to install remote controlled tail-lights for towing the Blazer behind an RV. Argh...

Lesson? Always check for damaged wires!!!!

 

Yeah it’s a joke that they put the harness there.I’m definitely gonna check wires before I go out and buy parts. Hopefully no more electrical problems for the us