Wiring problems - 2001 Blazer Trailblazer

89-LX

Forum Member
I'm having some more wiring issues with my blazer. I have a 2001 Blazer Trailblazer with a wiring nightmare that I hope anyone could shed some insight on for me on where to look. I'm good with cars, so I an do the work, but I'm just not too familiar with the blazer setup and I'm not going to dig into wiring blind.

Starting with the most recent issue, the overhead console (full trip, compass, etc) has been going on and off. Tomorrow I am going to test with my multimeter to see voltage going to the overhead console, but with a test light today on the pwr/gn, it was steady even thought the unit was resetting on and off or staying off. Could a data wire cause it do to this, or could it just be the unit itself going bad? I Which leads me into my second problem which I think is associated with this. I'm getting the speedometer erratic readings, ABS and brake light, and sometimes locking in 2nd gear and staying there. I rebuild the trans and put a newer transfer case in about a year about, and all was good until recently. It happens when there is water out or snow, but does happen when its dry just not as often. I replaced the VSS on the back of the transfer case, so that leads me to believe its wiring somewhere and not just that sensor. I dunno if there is another sensor down there that can cause this or not. My other thought was a bad BCM or wiring with both of the issues but I just dunno how this truck is setup.

My other issue I'm having is the damn power/heated seats. I fixed the power seat issue by jumping a new power wire to both seats, replacing the corroded wire under the drivers seat. That worked for awhile, but then my heated seats stopped working at the same time. The light still goes on for the heated seats on both sides, but they aren't heating up. I know that both seats didn't fail at the same time, but I am just wondering if they have a different power wire for the light/switch that controls a relay that has the power for the seats.

Btw, it happens when it snows all the time. But its pouring rain out, and no speedo/abs/brake light errors.

I appreciate if anyone can give me any help.

-David
 
Start with pulling codes first.
Two things that are common are a bad ignition switch (very common) and a loose ground (left kick panel).
Have someone with identifix run the problems.
 
I'd check both things that Rich mentioned. This screams a bad ground to me if all the positives are constant even while the devices are resetting, unless of course you tested the positives using the ground wire in the harness, then I would suspect a bad module somewhere in there.

On the other hand, Joe (s/n Duke on here) is great with wiring. You might be surprised at the price since more often than not he can diagnose the problem fairly quickly and get it fixed without just throwing parts/$$ at the problem. I used to fix all my own wiring and it was a headache, but I've found that often times it's more cost effective to just let a professional (Joe in my case) have at it for an hour or two than to keep replacing sensors/modules without knowing for 100% sure that it's the problem.
 
I'll check those out tomorrow.

Rich, I still need to do the fix for my 4L60E with the harness clips that are broke. Do you have those in stock? Also, I need to have my fill tube fixed, any chance I can bring it by the shop and pay you to fix it all up for me? I leave for Atlanta next weekend for 2.5 months and I want to get it all fixed up before then.
 
Ok, just an update if anyone can provide any input on the overhead console issue. The speedo has been working fine now so who knows.

I have the overhead with the mode selector for mpg, range, etc and I grabbed 2 of the same units off of junk vehicles at a junkyard but either one doesn't work. Now I know there is a chance it could be all 3 units that are bad. I checked the at the harness, and the orange is geting 12v constant, yellow shows no voltage (data wire), 2 dimmer wires show good voltage and dimming when lights are on, ground works, VSS shows voltage changes when driving, accessory gets power when key is in, temp doesn't show any voltage, and the RAT wire shows 2.5 volts when the key is out before the door is open.

So could it be 3 bad units, or maybe something else causing this?
 
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