Liftgate Control Module Problem - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum



Welcome Enthusiast! If you already own a Chevy TrailBlazer or GMC Envoy or perhaps thinking of purchasing such a vehicle, then you have come to the best TrailBlazer and Envoy site on the net! Rainier, Bravada, Ascender, and 9-7x owners welcome too!

You are currently viewing our site as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to search and post topics, communicate privately with other members, respond to polls, upload content, and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us.
Join Today!
Go Back   Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum > 2002 - 2009 TrailBlazer/Envoy Tech > 02-09 General Tech Q&A > General

General If it doesn't fit in any other forum

TrailVoy.com is the premier GMC Envoy Forum on the internet. Registered Users do not see the above ads.
Reply
 
Thread Tools
  #1  
Old 07-09-2009, 10:46 PM
salwan salwan is offline
Junior Member
 
2005 GMC Envoy SLE
Silver Blue Metallic 4.2L I6 4X4
Join Date: Jul 2009
Location: Toronto, On
Posts: 10
Liftgate Control Module Problem

I took my 05 Envoy to GM today to check why the remotes doesnt work anymore, nor does the rear wiper or rear defroster, and also the liftgate does not lock when I lock all doors from inside the car. The only way to lock it is manualy.

The dealership said that the LGM (rear body control module) has gone bad. But they scaned with the computer the car and they said that there is a short circut somewhere in the ground of the car, they showed me a module that is located under back seat on the driver side (where the fuses are) and said they suspect that it caused the module to fail. Any suggestions on this issue

Thanks!
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2  
Old 07-10-2009, 06:14 AM
Blazernut's Avatar
Blazernut Blazernut is offline
Western Canada Chapter
 
2003 TrailBlazer and '09 Kadillak Eskalade __
sExY Dark Gray Metalic 4.2L I6 4X4
Join Date: May 2006
Location: Vancouver BC
Posts: 6,409
If in fact a short has occurred it is usually in the rear liftgate where the wires are flexed repeatedly. You can search that area with a meter for continuity and look for a ground. It may be intermittent so a visual of the wires WHERE THEY PASS THROUGH OPENINGS is sometime the best bet.

The module may have failed but fuses and the short should be checked/repaired first. I believe you can get a module on Ebay for a good price. Then you get the dealer to program it to your truck
__________________
Bill

Let's get a Meet going!
Reply With Quote Quick reply to this message
  #3  
Old 07-10-2009, 04:34 PM
salwan salwan is offline
Junior Member
 
2005 GMC Envoy SLE
Silver Blue Metallic 4.2L I6 4X4
Join Date: Jul 2009
Location: Toronto, On
Posts: 10
Solved the problem

Thank you so much for the advise. It was a wire that was cut for some reason and it caused the module not to work. I reconnected the wire and the module is fine. thanks again

Salwan
Reply With Quote Quick reply to this message
  #4  
Old 08-11-2009, 01:25 AM
Chevy492 Chevy492 is offline
Junior Member
 
2002 Chevy TrailBlazer LS
Midnight Blue Metallic 4.2L I6 4X4
Join Date: Sep 2008
Location: Kansas City, MO
Posts: 19
Quote:
Originally Posted by Blazernut View Post
If in fact a short has occurred it is usually in the rear liftgate where the wires are flexed repeatedly. You can search that area with a meter for continuity and look for a ground. It may be intermittent so a visual of the wires WHERE THEY PASS THROUGH OPENINGS is sometime the best bet.

The module may have failed but fuses and the short should be checked/repaired first. I believe you can get a module on Ebay for a good price. Then you get the dealer to program it to your truck
SO i have the same issue and i had some cut wires up at the top of th elift gate and i put them back together and it sounded like it locked the door but didn't turn the module back on for continous use so i was wondering how i would check for the ground to be wokring i have a a multi tester but im not sure what im looking for with it... if you know let me know what i should do im prolly gunna have to end up getting a new bcm but i had hope when i heard some action when i connected the wires back together...
Reply With Quote Quick reply to this message
  #5  
Old 08-12-2009, 12:03 AM
salwan salwan is offline
Junior Member
 
2005 GMC Envoy SLE
Silver Blue Metallic 4.2L I6 4X4
Join Date: Jul 2009
Location: Toronto, On
Posts: 10
Quote:
Originally Posted by Chevy492 View Post
SO i have the same issue and i had some cut wires up at the top of th elift gate and i put them back together and it sounded like it locked the door but didn't turn the module back on for continous use so i was wondering how i would check for the ground to be wokring i have a a multi tester but im not sure what im looking for with it... if you know let me know what i should do im prolly gunna have to end up getting a new bcm but i had hope when i heard some action when i connected the wires back together...
I looked for Voltage where the wires are at the top of the liftgate when I was fixing my problem. 2 of the three were at 12V D/C and the 3rd one was 0V.

when you close and open the liftgate do you hear the module working? and also check if your back wiper is working after you put back the wires.

Hope this helps.
Reply With Quote Quick reply to this message
  #6  
Old 08-12-2009, 01:05 AM
Chevy492 Chevy492 is offline
Junior Member
 
2002 Chevy TrailBlazer LS
Midnight Blue Metallic 4.2L I6 4X4
Join Date: Sep 2008
Location: Kansas City, MO
Posts: 19
alright heres the update...... i checked the orange wire that goes from the lift gate to the body at the top with my tool that lights up when there is power and it wasn't lighting up so...... i checked both fuses and and on ewas blown so i replaced it and it seemed to kick the module on becaus ei could here it click....... like 5 months ago when i was messing with it the module seemed to make a humming niose and when i would close the lift gate half way it sound like the door was locking but now it does nothing........... so i was wondering which wires you tested to see if they were getting power because i think the orange at the top of the liftgate is the power and one is the ground then there are two smaller ones i believe blue and brown so which di dyou check for the 12 v current? ohh and i might add that my license plate lights are wokring so that means possible good ground? i was just wondering if im making progress in accompleshing this problem ha thanks let me know any new info that might work?
Reply With Quote Quick reply to this message
  #7  
Old 08-12-2009, 04:08 PM
salwan salwan is offline
Junior Member
 
2005 GMC Envoy SLE
Silver Blue Metallic 4.2L I6 4X4
Join Date: Jul 2009
Location: Toronto, On
Posts: 10
Quote:
Originally Posted by Chevy492 View Post
alright heres the update...... i checked the orange wire that goes from the lift gate to the body at the top with my tool that lights up when there is power and it wasn't lighting up so...... i checked both fuses and and on ewas blown so i replaced it and it seemed to kick the module on becaus ei could here it click....... like 5 months ago when i was messing with it the module seemed to make a humming niose and when i would close the lift gate half way it sound like the door was locking but now it does nothing........... so i was wondering which wires you tested to see if they were getting power because i think the orange at the top of the liftgate is the power and one is the ground then there are two smaller ones i believe blue and brown so which di dyou check for the 12 v current? ohh and i might add that my license plate lights are wokring so that means possible good ground? i was just wondering if im making progress in accompleshing this problem ha thanks let me know any new info that might work?
I have uploaded a picture of the wires that I checked for continuity since you have a tb and I have an envoy the wires might be different color. The wires on my truck were the small orange and brown wires(the last set of wires on the left in the picture). The license plate lights were working for me too when the module wasn't working. Check if your rear wiper is working, I believe you forgot to say if you checked it after reconnecting the wires. keep us updated. and hope this helps.

Salwan
Attached Images
 
Reply With Quote Quick reply to this message
  #8  
Old 08-12-2009, 06:43 PM
Chevy492 Chevy492 is offline
Junior Member
 
2002 Chevy TrailBlazer LS
Midnight Blue Metallic 4.2L I6 4X4
Join Date: Sep 2008
Location: Kansas City, MO
Posts: 19
ohh yeah my bad i was thinking of that when i turned off the computer last night............ no the wiper doesn't work defogger doesn't work the lock doesn't work and washer fluid as well but yes the license plate lights work ha.... but i was wondering once you tested the wires and saw that the on e was at 0v what did you do to get it working was it split somewhere? my multi reader isn't working so im going to borrow my friends tongiht and will get back with some news.... i appreciate the concern man
Reply With Quote Quick reply to this message
  #9  
Old 08-20-2009, 12:38 PM
DSpoelma's Avatar
DSpoelma DSpoelma is offline
Junior Member
 
2004 Chevy TrailBlazer LT
Black 4.2L I6 4X4
Join Date: May 2009
Location: Colorado
Posts: 11
First post -

I recently purchased a TB, and upon leaving with the car, the remote entry worked for a couple of days, then stopped. I figured remote battery was the issue, changed it reprogrammed the remote. Still nothing, searched the net, found this site, and began researching what could be the issue. Here is what I see: When I shut the tailgate, it acts as if the tailgate is locking, the wiper, defrost, and license plate lights all work. I checked for fuses, didn't see anything out of the ordinary - (BTW, which fuses should i specifically be looking at). I pulled off the rubber boot housing the wires last night, went through the wires, and did not feel anything that seemed like it was a broken wire, but will check continuity tonight. Any help/suggestions as to what to do next would be helpful. Thanks, and great site!

Dan

PS - when programming remote, it takes about 3 - 4 minutes of holding the lock/unlock button to get the doors to cycle lock/unlock.
Reply With Quote Quick reply to this message
  #10  
Old 09-01-2009, 03:55 PM
tfair tfair is offline
Junior Member
 
2002 GMC Envoy SLE
Pewter Metallic 4.2L I6 4X4
Join Date: Aug 2009
Location: Pittsburgh, Pa
Posts: 3
Same Problem

Hi guys,

I've got a 2002 Envoy with the same problem(s). I've followed the thread pretty closely and have determined that the larger orange (hot) wire in the liftgate was snapped. Tonight, i'll try to get this spliced back together and see what is working or not. My question is this: the two orange wires are hot, the brown wire is a ground, the larger black wire appears to be a ground as well, but what is the small blue wire for?

I temporarily spliced the hot back together and left the tailgate up, i've seen that the license plate lamps now work, but the wipers didn't (again tailgate up, not sure if they'll work with the gate up). jumped in and programmed the keyless remote and after depressing the lock & unlock buttons on the remote, the horn sounded and i turned the key to on and off and removed the key. got out and closed the door, remote still not functional.... Curious as to if the tailgate needs to be down while programming.

Any help would be greatly appreciated. Cheers and have a great day
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum forums, you must first register.

Please enter your desired user name, your email address and other required details in the form below.
(Only letters, numbers, dashes and underscores are permitted for user names)
The user name that you choose is permanent and can never be changed.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


» Sponsors

Advertising Info

All times are GMT -4. The time now is 04:13 PM.


Chevy TrailBlazer and GMC Envoy Enthusiasts - Copyright 2004 - 2009 All Rights Reserved.
All trademarks referenced herein are property of their respective owners.
RSS Feed