2008 Chevrolet Trailblazer electrical issues

Tiny
JGWARDYN
  • MEMBER
  • 2008 CHEVROLET TRAILBLAZER
  • 4.6L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 80,000 MILES
I have numerous electrical issues on my 2008 TrailBlazer that started happening 3 weeks ago.( In order of occurrence)
1. Rear wiper stopped working (works now), The rear Hatch lock would not unlock, now lock continuously cycles on/off while hatch is open and the vehicle is not running. It stays locked with hatch down and vehicle running.
2. Random warning lights came on dash display while driving; then all the warning light came on, the gauges all when to zero. Stopped vehicle then restarted, then half the warning lights worked. Noticed clock reset. All issues ARE gone everything is working.
3. Wheel sensor traction control warnings(random; can clear by stopping vehicle and cycling on/off ignition switch).
4. No open door chime (right side speakers?)
5. Unable to program TPM. (Bought new tires yesterday).
Do I have an Ignition switch issue or wiring harness ground issue? Can GM diagnostics equipment isolate the issue?
If I take it in to a shop what questions should I ask?
Thursday, August 14th, 2014 AT 5:12 PM

12 Replies

Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Sounds like you could have a bad body control module yes a high end or gm scan tool should be able to diagnose it.I would bring it to the shop tell them all the symptoms and see what they can find wrong.
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Thursday, August 14th, 2014 AT 8:46 PM
Tiny
JGWARDYN
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Can I diagnose a bad 'body control module' with simple troubleshooting tools like a VOM & a continuity tester? I have access to a OEM service manual electrical schematics.
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Friday, August 15th, 2014 AT 6:03 AM
Tiny
SATURNTECH9
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Before anything is tested or unplugged the first thing I would do is scan the vechile with a professional scan tool that can read all the computers not a diyer scan tool or free code read at the auto parts store. They cant read all the computers in the car. Thats the starting point and depending on the codes you may need a professional scan tool to diagnose the problem. The newer the car the dependent you are to need a professional scan tool to diagnose the car.
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Friday, August 15th, 2014 AT 6:48 AM
Tiny
SATURNTECH9
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Also make sure you write down all the exact code number's not code descriptions?
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Friday, August 15th, 2014 AT 6:53 AM
Tiny
JGWARDYN
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Is the lift gate issue a separate problem? Does the service tech need to perform separate scans on the Body Control Module and the Lift Gate control module? I assume it will do both but just asking.
Also, I keep reading about grounding being an issue. Particularly corrosion at the G201 harness ground point under the console.
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Friday, August 15th, 2014 AT 7:45 AM
Tiny
SATURNTECH9
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If they all started about the same time I would say there related. Also every computer must be scanned meaning every computer in that car. Also again before unhooking wires unplugging computers etc you must check codes. So you dont taint the codes results.
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Friday, August 15th, 2014 AT 8:25 AM
Tiny
JGWARDYN
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OK thx for your help.
I have a plan now. I have enough info now to ask the right questions to the service tech. Once I get the codes I can decide a course of action. I can provide you with feedback on successful corrective actions if you want it.
Again thx
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Friday, August 15th, 2014 AT 8:46 AM
Tiny
SATURNTECH9
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Yes please keep us up to date so we can pass it on to others in need with the same issue.
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Friday, August 15th, 2014 AT 12:26 PM
Tiny
JGWARDYN
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This is a continuation of a thread we started last week about numerous electrical issues with my 2008 Trailblazer.
Just had the local auto-electrical tech scan my vehicle. He said there were no current codes BUT numerous stored codes.
PCM
U1064
U1301
BCM
U1305
U1064
U1160
U1096
He stated that I had intermittent communication & data loss.
Something about low voltage signal code on the tester. The tech said it could be any of modules in the serial data circuit causes the low voltage condition which would cause the system to wig out.
His primary guess would be the instrument dash panel. But it could be the BCM. He stated the instrument panel would 100 to 1 more likely than the BCM.
Everything on the vehicle working except the rear wiper. Plus the rear lift gate lock cycling when open & car not running. The scanner did not show a current lift gate module code. He thought there is a bad wiper motor.
Ant thoughts on the intermittent loss of the communication bus?
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Friday, August 22nd, 2014 AT 9:52 AM
Tiny
SATURNTECH9
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The instrument panel shouldn't effect the locks those are all communication codes the bcms on the cars do fail alot other modules also. Its hard to say without doing some testing did the rear wiper stop working about the same time as everything else started happening?
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Friday, August 22nd, 2014 AT 9:17 PM
Tiny
JGWARDYN
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Yes, the electrical issues all were noticed after the rear wiper stopped working. The only warning lights before that was the Stabilitrac. Which has been an ongoing random issue for 2 yrs.
The rear washer pump is still working but the wiper motor isn't.
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Sunday, August 24th, 2014 AT 4:57 AM
Tiny
SATURNTECH9
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Have them diagnose that rear wiper inop it might lead to the other issues.
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Sunday, August 24th, 2014 AT 6:35 PM

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