Good Afternoon!

I have a 2001 GMC Jimmy SLT w/ 175K with a bunch of electrical issues that I am sure related.

Sporadically across my ownership the electrical problems have become more evident, initially it would just be the headlights cutting out momentarily while driving at speed, especially if I hit the brakes. Later on, when I hit the brakes my cluster would go out & turn back on with all the warning lights flashing on. Now as time progressed, my radio would also cut out as well, sometimes if I use my power windows, the radio would cut out momentarily as well. When I shut off the car, the retained accessory function & automatic door locks only function half the time. Now it has gotten to a point where it has become a problem because, I will shut off the car & when I get back to the car, it has a hard time starting because the PCM/BCM have reset. The truck has to relearn fuel trims, & the time is reset on the radio. It does this so often now that I am concerned it wont be able to pass state inspection.

I have tried my best to trace a bunch of grounds, found 3 behind the instrument cluster that looked fine but I cleaned & tightened for good measure. Cleaned up the three in front of the battery. Checked on the one behind the passenger side head. I recall having a hard time trying to track down the ground on the passenger side in the cabin against the firewall or the one behind the drivers side head.

Any ideas? I'd hate to get rid of this truck, she runs good, engine is strong, no leaks, etc.

Thanks in Advance!

 

Have u do any research regarding ignition switch? The ignition switches are a well known issue on these blazers..........that can cause a variety of issues, do a search regarding ignition switches on here.....u should find an overwhelming bit of reading material

 

Thanks!

I have thought about the ignition switch but became skeptical when I was losing power to the BCM//PCM & everything else. I may look at getting a cheap one just to see if it makes a difference!

Also I forgot to add, if I leave the door open w/ the dome light on, it will drain my battery within 5-10 minutes. Which is strange because I have left two cell phones charging in the car overnight & she starts up just fine.

 

Just figured I'd give an update,

On my way home after dealing with the same issues again as I sat in traffic, I thought what could tie all these things together... I figured I check out the dimmer/headlight switch. I took the switch apart & cleaned it off with Q-Tips & rubbing alcohol. There wasn't any corrosion, but the contacts and board were pretty dirty. The board was covered in dielectric grease that attracted dust & dirt. Cleaned everything off & reassembled. I will report to see if its any help!

 

Check you under dash grounds.

 

Yessir!

Just another update, cleaning my dimmer/headlight switch did not change my situation, although the switch does work better now. I pulled apart the right side of my dash & everything looked good. Harnesses were intact, etc. The grounds were tight & they were not corroded. However, just like the grounds on the driver's side dash the grounds were screwed into painted metal. I sanded down the mounting points & buttoned everything up. We'll see trw if it makes a difference.

BTW, the passenger side dash grounds are easy to access, they are right behind the top part of carpet where it meets the dash. I hope you don't mind the updates, I figure I throw em up for the next poor soul who has similar problems, hahaha.

If this doesn't do it, I'll just run a ground wire from the battery to the firewall. & if it still doesnt work it will be goodbye.

 

Thanks for updating. This could be helpful to someone.

 

Just a quick thought...How's that alternator doing? When they start failing, they throw out all sorts of weird symptoms.. Some have even been known to leak AC into the system when they start to go.. There's so many ways an alternator can fail , it'll have you chasing ghosts...

Just a thought for whats it's worth.

 

Check the wiring harness from the bottom of the under hood fuse box to the firewall. The box can burn up on the bottom and appear fine from the top.

Mine was shorted and burned against the abs motor bracket. I had no headlights and two crazy lists of electrical problems. One when the truck was dry and another when it got wet. I had to be home when the street lights came on and the horn blew non stop through the car wash. Everyone was giving me stink eye. Funny how embarrassing times turn into happy memories.

Thanks for the updates. I hope you find it, in my case you're the next poor soul with similar problems.

 

Just to reaffirm the info above , I think 07nhbpsi and Rusty Nuts have you going in the right direction...

Don't throw in the towel just yet....