fullyauto12
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- Feb 6, 2025
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Hey All,
I have a very puzzling electrical issue that has me stumped. I've done lots of investigating and it has led me to get closer, but I'm beginning to get out of my scope of skill and hoping someone has some advice of guidance? Sorry for the ridiculously long post, but I have been trying to diagnosis this myself for a month now and am at dead end and want to include all I've done
The Issue:
**We had some freezing rain here in NC about a month ago and my 2009 Tahoe was outside for the whole thing and it got a lot of ice build up during this time. The next day, it had all melted and I got into drive it. Got down the road and a bunch of crazy electrical issues began happening.
-RPM, fuel, and oil gauges would lose power momentarily and regain power
-ABS and stablili-trak lights came one
-Service suspension, service 4WD, service trailer brake service ABS
-Whatever gear the transmission was in when it first had issues - would stay the gear....(I.E if the issues happened at 60 and it was in 4th gear...it would STAY in 4th gear, even when slowing down...and if it happened when you started driving it would stay in 1st)
-clicking down by the E-brake
So.. I towed it to Chevy about a week later (soonest they could get me in), and had them look in to it. By the time they looked at it, the issue had completely gone away and they said it was fine. So we drove it home and then to work the next day, about 45 minutes into the drive it happened again. I was able to get it home...barely...I've been looking into many different things to try and fix it.
The Fixes:
*I started investigating and first figured the clicking was comin from the Cabin Fuse Relay Junction Box (Or power distribution module). Figured it was just not grounding properly or a bad internal relay, so I replaced the junction box completely. and that took the clicking away, and it seemed to run fine, except all the ABS errors were there, and the parking brake light was on and all that stuff, but it drove fine. I plugged into the OBD reader, and had 0 connection with the ABS module.....So I rechecked my junction box, and realized that I had forgotten to plug in a plug in the back of the distribution module. Plugged it in...and BOOM, issues all back like they originally were!
*Plugged in my code reader to see what changed, and it will connect to the ABS module, then when the power glitch happens, disconnect, and repeat.
*I got an electrical manual to figure out just what that 7 wire plug did to cause so many issues. The plug in question is X3 on this image I'm attaching a pin-out and a picture of what it looks like (green plug). it has a few grounds, some data connections and a speed sensor wire.
*I'm not 100% sure that the ABS module that has actually gone bad (I'm sure its $1500+ to replace). But I could be wrong. It could be a lose ground, but who knows...
*I also cleaned all the chassis grounds (2 behind front tires, rear chassis, ground stud under the windshield dash)
*Checked the main ground cable block and chassis connections
*Checked the ground strap from the block to the frame
Does ANYONE know what this specific plug grounds or controls?
I have a very puzzling electrical issue that has me stumped. I've done lots of investigating and it has led me to get closer, but I'm beginning to get out of my scope of skill and hoping someone has some advice of guidance? Sorry for the ridiculously long post, but I have been trying to diagnosis this myself for a month now and am at dead end and want to include all I've done
The Issue:
**We had some freezing rain here in NC about a month ago and my 2009 Tahoe was outside for the whole thing and it got a lot of ice build up during this time. The next day, it had all melted and I got into drive it. Got down the road and a bunch of crazy electrical issues began happening.
-RPM, fuel, and oil gauges would lose power momentarily and regain power
-ABS and stablili-trak lights came one
-Service suspension, service 4WD, service trailer brake service ABS
-Whatever gear the transmission was in when it first had issues - would stay the gear....(I.E if the issues happened at 60 and it was in 4th gear...it would STAY in 4th gear, even when slowing down...and if it happened when you started driving it would stay in 1st)
-clicking down by the E-brake
So.. I towed it to Chevy about a week later (soonest they could get me in), and had them look in to it. By the time they looked at it, the issue had completely gone away and they said it was fine. So we drove it home and then to work the next day, about 45 minutes into the drive it happened again. I was able to get it home...barely...I've been looking into many different things to try and fix it.
The Fixes:
*I started investigating and first figured the clicking was comin from the Cabin Fuse Relay Junction Box (Or power distribution module). Figured it was just not grounding properly or a bad internal relay, so I replaced the junction box completely. and that took the clicking away, and it seemed to run fine, except all the ABS errors were there, and the parking brake light was on and all that stuff, but it drove fine. I plugged into the OBD reader, and had 0 connection with the ABS module.....So I rechecked my junction box, and realized that I had forgotten to plug in a plug in the back of the distribution module. Plugged it in...and BOOM, issues all back like they originally were!
*Plugged in my code reader to see what changed, and it will connect to the ABS module, then when the power glitch happens, disconnect, and repeat.
*I got an electrical manual to figure out just what that 7 wire plug did to cause so many issues. The plug in question is X3 on this image I'm attaching a pin-out and a picture of what it looks like (green plug). it has a few grounds, some data connections and a speed sensor wire.
*I'm not 100% sure that the ABS module that has actually gone bad (I'm sure its $1500+ to replace). But I could be wrong. It could be a lose ground, but who knows...
*I also cleaned all the chassis grounds (2 behind front tires, rear chassis, ground stud under the windshield dash)
*Checked the main ground cable block and chassis connections
*Checked the ground strap from the block to the frame
Does ANYONE know what this specific plug grounds or controls?
