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2002 gmc envoy_slt
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Discussion Starter · #1 · (Edited)
Hi, My 2003 envoy (150,000 miles) gives a "Unknown Driver" message in the instrument cluster when attempting to start. Additionally, the power locks, dome lights, power windows, radio, and headlights all don't work.

The wipers, power seat (both sides), power mirror and hazard lights work.

The headlights/tail lights work only when the ignition is turned to the on position. High beams do not work, also will not flash to pass

I replaced the ignition lock cylinder a few thousand miles ago. The driver power seat heater quit working and I took it to a guy to get an aftermarket seat heater installed. He also agreed to weld a broken part in the power seat frame that prevented the front part of the seat from going up and down.

When I went to pick it up from him. He tired to start it and it gave the "Unknown Driver" error code. I was about to do the procedure to sync the key fob when I noticed the power locks and windows and radio all didn't work.

He tapped into a switched fuse to get the power for the seat and tapped into the ground stud on the firewall near the brake master cylinder. He did remove the driver seat to complete the weld repair and he unplugged the under seat wiring harness.

I searched trailvoy on my iphone and we attempted to check a few of the suggested trouble points. The maxi fuse is good, the battery is fully charged, power is hitting the rear fuse panel under the rear seats. I finally gave up having him fix anything (as more people from the shop started fiddling with stuff on my Envoy). I had the Envoy towed back to my house and tonight I will continue trying to fix the problem.

If you have any suggestions for me to try please post them. I'll leave the computer running. I will update this thread when I solve the problem. Luckily I don't have to show up at work tomorrow so I have a bit of a buffer.

THINGS CHECKED:
- Maxi Fuse good (removed and continuity tested)
- Rear seat fuse panel is receiving power
- Battery fully charged
- No OBD2 trouble codes
- Ground Splice Pack G201 under dash passenger footwell on center console (appears OK, removed, inspected and retightened)
- Each fuse in both fuse boxes (ok)
- Wiring harness to rear tailgate, inspected for shorts or damage (ok)
- Replaced fuses to ECM (even though they checked OK)
- Removed, Inspected and Replaced connectors to ECM
- Disconnected Driver Door Module and tired to start (trying to eliminate that as a problem)
- Disconnected Splice Pack 306 under passenger rear seat and tried to start (trying to eliminate that as a problem)
- Removed driver seat to inspect for damage (none found), inspected wiring harness under seat - nothing found
- Removed door sill trim, drivers door, to inspect wiring harness for damage, nothing found
- Removed, inspected and re-installed firewall ground connection

WHAT I'M CHECKING NOW
- Giving up for the night, in the morning will check here one more time and call to have Envoy towed to dealership :-(

Dealer Repair Attempt #1
- Replacing the BCM Body Control Module (under the rear seat) $700


WISH ME LUCK :) Mon Jan 26, 2015
 

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2002 gmc envoy_slt
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Discussion Starter · #2 ·
Finally Solved

The dealer found the computer under the rear seat was not functioning. The dealer also found that the fuse panel under the hood was malfunctioning. Total repair cost $1400.

I guess the seat heater installer removed and replaced several fuses in the panel as he tried to determine which one to tap into. He mashed them down so far that they shorted out. I also think when he wrestled the driver seat out he hit the BCM computer under the rear seat.

The items in my threat listed above are still good things for you to check if you encounter a similar problem.
 

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Unknown driver, there is a ground left side rear inside pull back molding, closest to rear hatch, clean it and make sure to leave battery disconnected for 2 hours, this will also fix pass lock coming on when driving,
 
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