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2005 gmc envoy_sle
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Discussion Starter #1
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!
 

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Western Canada Chapter
2003
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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. :undecided Then you get the dealer to program it to your truck :thumbsup:
 

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2005 gmc envoy_sle
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Discussion Starter #3
Solved the problem

:thx 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
 

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2002 chevy trailblazer_ls
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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. :undecided Then you get the dealer to program it to your truck :thumbsup:
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...
 

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2005 gmc envoy_sle
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Discussion Starter #5
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.
 

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2002 chevy trailblazer_ls
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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?:cool:
 

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Discussion Starter #7
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?:cool:
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
 

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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
 

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2004 chevy trailblazer_lt
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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.
 

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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
 

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Its fixed

Ok - so i grabbed the multi-meter from the office and went out to test out the harness again. Turns out that I had 2 snapped wires in that rubber boot between the body and the tailgate.

The larger orange one was snapped as well as the smaller light blue wire. Both appear to be hots. After reconnecting these two wires all electical functionality returned to the truck and to the tailgate. Good luck to all of those who come across this post and hope this helps others as well. Thanks to all who posted previously which helped me to identify the problem.

Cheers all
 

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2003 gmc envoy_slt
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Same problem here too!

Wow! This seems to be the going issue lately.

I have a 2003 Envoy and its showing off the same issues. Yesterday the key fob stopped working. I went to Target (at 8pm) and nobody waited on me. SO I reached over the counter and used their battery tester. Shot right up! So I figured the fob lost its mind. Went home grabbed the second fob and that didn't work either. Oh oh... just finished paying for the Car. Ran perfect until the last payment..figures! :)

Anyways, I googled this issue and someone mentioned that it could be the LCM (Liftgate control monitor). I checked both rear fuse box 3 and 19 I think (says LGM on manual) and both checked out ok with my multimeter. Damn... hoped it was that simple. Tested the Rear Windshield Wiper and that's dead too. Found you guys now. Misery loves company!

So, I unplugged the tailgate harness and tested the 3 orange cables. They're Hot 12V each. Black and Brown looks like are ground. On the other side of the harness I can't seem to get anything from any lead to the others. No connectivity.

Right now. No Remote Keyless Entry (RKE), no Rear Wipers. Licence Plate lights were working. Actually one of the bulbs were blown. Tested the leads and they're 12V.

So I'm guessing I don't have a short issue either, am I right?

Chris
 

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Ok - so i grabbed the multi-meter from the office and went out to test out the harness again. Turns out that I had 2 snapped wires in that rubber boot between the body and the tailgate.

The larger orange one was snapped as well as the smaller light blue wire. Both appear to be hots. After reconnecting these two wires all electical functionality returned to the truck and to the tailgate. Good luck to all of those who come across this post and hope this helps others as well. Thanks to all who posted previously which helped me to identify the problem.

Cheers all
Sorry, I'm new to this. When you mean snapped, do you literally mean that they're broken/disconnected? My light blue is 0V. Is yours 12v? Tx!
 

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It worked!

Holy Cow!

Yep, the blue cable was snapped and is indeed hot (12v). I did have a problem threading it back into the tight rubber sleeve. Any tips there? I instead got a longer cable and twisted them together for now.

:thx:Thanks so much for the pointers in this forum.:hail: I can't believe that it was such a simple issue albeit buried. :woohoo:
 

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Tailgate issues

Glad that you found this thread and that it helped. I've done a simple fix on it and plan on doing a more professional job of it later by running new wires for all the leads into the harness through the rubber boot. The little wires are a pain to get thru it, so i figure pushing all 5 wires through at one time might make it a little easier.
 

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heres another with the same problem :) my 02 TB rear wiper and defroster isnt working at all. i did have problems with the fob when i first got it 2 months back, and i seemed to fix it by replacing a relay under the back seat, found that out by tapping on it when we were trying to figure out why the back hatch wouldnt unlock. but yea, im going to look closer for snapped wires, cuz id like to save my money and not have to get a LCM for it. thanks for all your time posting all this info, and ill be back to let you know what i find...man i wish i would have came across this before winter fell :p

~TIP
 

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2007 chevy trailblazer_ls
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Another poor schmuck here with an 07 TB with a non-functioning key fob and rear windshield wiper. The problem has been intermittent over the last few months, locks would be working fine then all of a sudden nothing. Then magically start working again and now nothing for the past couple weeks. It's got to be a broken wire given the intermittent functionality, but my problem is that I can't even get the lift gate to open when the key fob isn't working. Manually hitting the power locks from the inside doesn't open the rear lift gate. Fuses check out fine.

How can I get this lift gate open???

The problem really sucks because we have a baby, and have to wrangle the stroller out of the back by lifting it up over the rear seats.

Help please!!!
 

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hey sidetrack, i had somewhat the same problem when i first got mine. i seemed to fix it by replacing a relay that is found under the back seat, driver side. cant remember exactly which one, but how i found it, was when it wasnt working i tapped on each relay with a screwdriver until one started to work, hope this helps
~TIP
 

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hey sidetrack, i had somewhat the same problem when i first got mine. i seemed to fix it by replacing a relay that is found under the back seat, driver side. cant remember exactly which one, but how i found it, was when it wasnt working i tapped on each relay with a screwdriver until one started to work, hope this helps
~TIP
I'll be sure to give that a try as well. I haven't been able to put aside any time to dig into the wires yet, but I plan on having a look this weekend. I'll be sure to report back what I find. Thanks.
 
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