Rear gate Wiper does not work/remote lock don't work - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

bmcgregor3 · #1 06-25-2008, 07:06 PM

I recently installed an AUX GM aux input adapter in our 2004 Envoy XL. Every thing worked fine for about a week then the lock remotes stopped working. I changed the batteries in the remotes and tried reprogramming the remotes and still they did not work. Then I noticed that the rear window wiper was not working and when I hit the auto door locks the rear gate did not lock as well. I checked all fuses and did not find any bad. I do not know how to check the relays. I have since removed the AUX GM and nothing changed so I guess that was not the problem. I pulled the rear gate apart and noted that some of the wires have power.

Does anyone have any ideas. Where can you buy relays or is that likely not the problem.

Thanks,
Bruce

PROSPHOTO · #2 06-25-2008, 08:27 PM

Sounds like a lift gate module failure...but I'm not certain

I'm sure other members that have experienced your concern will chime in

**tblazed** · #3 06-25-2008, 10:21 PM

Could be one of the wires that passes through the rubber boot at the top of the liftgate. They get bent with every opening and closing. Do the license plate lights work? If a broken (open) ground wire, the lights will be dead too. You should find Orange (x2) 12V Battery voltage, black GND, Light Blue Class 2 serial data, and Brown Left side marker power for the license plate lights.

bmcgregor3 · #4 06-27-2008, 09:52 PM

Yes the license plate light works. I just can't find a relationship between remotes and rear gate wiper/lock. Also the cabin light do not operate when the door open. They will turn on manually but not with the doors.

Thanks for the help so far!!

PROSPHOTO · #5 06-28-2008, 08:26 AM

The lock operation and keyless entry operation are through the Lift gate module, so is the control for the rear wiper...that's the relationship that ties the two problems together

You may only need the module re-flashed, but you may need the module replaced (which would also require programming)

Programming must be done by the dealer...that may be your best solution at this point

**tblazed** · #6 06-28-2008, 09:22 AM

Quote:

Originally Posted by bmcgregor3

Yes the license plate light works. I just can't find a relationship between remotes and rear gate wiper/lock. Also the cabin light do not operate when the door open. They will turn on manually but not with the doors.

Thanks for the help so far!!

As Prosphoto said the liftgate module does several functions. It contains the RF receiver for the key fobs. It communicates with the body control module via the Class 2 serial data bus on the lt blue wire. You could have a broken lt blue wire. Without that module communicating you will get symptoms like you describe. Sometimes the module itself fails but I would sure look at the condition of those wires where they go through the rubber boot first to make sure they are intact, because replacing that module and having the dealer program it can run several hundred $$.

bmcgregor3 · #7 06-30-2008, 08:54 PM

Thanks for all the advice. I will check the wires this weekend.

aucobalt · #8 01-07-2009, 05:03 PM

BMC, were you able to resolve this problem??

My '02 TB LTZ is having the same issues (minus the key-fob)

Thatoneguy22 · #9 01-31-2009, 01:00 AM

I have the same problem with my 2002 TB and also my dome lights wont go off without pressing the override. First of all, I was wondering if the dome lights are related to the rear body control module or not and how to fix that maybe. And second, what problems would it cause If I were not to replace my module. I understand the keyless entry, rear wipers and defroster won't work, but do you know if anything else would malfunction and possible cause death of some sort? Just wondering.

marczsport · #10 05-16-2009, 07:22 PM

When I started reading this thread, it sounded like I could have written it! Same exact problems: keyless entry does not work and rear wiper does not work on my 06' Envoy SLT.

This is VERY frustrating because it is an intermittent problem, and of course never happens when I'm at the dealer. The Envoy is still under warrantee, but seeing as "nothing is wrong" when I bring it to the dealer, they don't fix anything!

I'm going to check the wires as described elsewhere in the thread- I"m hoping one is just loose or partially damaged so I can do a quick fix.

FWIW: When the keyless entry does not work, it is impossible to open up either the rear hatch or rear window! Talk about frustrating!!