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07 TB rear hatch wont lock all the time

25K views 15 replies 9 participants last post by  GKulback 
#1 ·
I noticed something weird today.

When I press the "lock" icon on the keyfob once, it locks all the doors on my TB. Pressing twice does the same but with a honk.

Either way I lock it, 9 times out of 10, I can still walk up a few seconds or minutes or even hours later and press the rear hatch button on the truck, and it will open the hatch. :confused:

The factory honking alarm does go off, but the hatch opens.

Am I missing something obvious here? :crazy:

Somebody is going to tell me its in the manual. :)

Mike
 
#2 ·
I just realized that mine does the same thing. I didn't realize it until just now. I tried opening it once when I thought the truck was locked, but it wasn't and the alarm went off. Now that I think about it, anyone can just go up and get in like that and quickly disable the alarm. I didn't get a manual, so does anyone have more info on this?
 
#3 ·
The power locks aren't locking your hatch or it wasn't fully pushed shut. I remember somebody else having a similar issue a while back. With the doors locked, the hatch should also be locked and not open. I've tried to open mine in the past with the locks locked and it shouldn't, and didn't, open. (BTW: It takes a good firm push to latch the glass/hatch on mine, could you possibly of simply not closed the glass tight enough?)

Since you both have '07s, I'd be inclined to bring it back to the dealer and have them correct the problem. Could be an issue with the tailgate module, faulty latching mechanism or as simple as a loose connection inside the door.
 
#4 ·
Mine DID the same thing. After 3 trips to the dealer and numerous fights with the service manager they finally fixed it. There is a TSB on this issue but they claim “that was not my problem”, either way its fixed. After we convinced them that it did it. (Mine never did it for them)
 
#5 ·
Where did you find the TSB on this? I asked the dealer about anything else that needed to done to the truck last time I was there and they said no, so I doubt they would know what I'm talking about if I asked. If I bring it to them, then maybe they'll get it done. Thanks.
 
#6 ·
I tried mine this morning before work and it was locked. At work it wouldnt lock, and after I got home I pressed the fob and walked away. I just went out and tried it. Unlocked. :worried:

I just figured out if I close the hatch 3 or 4 times and keep trying to lock it, it will eventually lock. PITA to stand there and d%$k with this hatch lock. :mad:

BACK to the dealer. :x

The TSB# would be great to have. I will search for it tomorrow if nobody here has it.

Nighty night. :yes:

Mike
 
#7 ·
Here's some TSBs. These may help in diagnosing the condition you are having:

Document ID# 2011600
2007 Chevrolet TrailBlazer - 4WD


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Subject: Liftgate Module Replacement - keywords communication defog defogger fob glass HVAC key keyfob learn LGM lock module monitor pressure rear replace rke sensor tire TPM wiper #PIT4394C - (09/13/2007)



Models: 2006-2007 Buick Rainier

2006-2008 Chevrolet Trailblazer models

2006-2008 GMC Envoy models

2006-2008 Saab 97x models




--------------------------------------------------------------------------------

This PI was superseded to update model years. Please discard PIT4394B.


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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
There are several conditions which are often diagnosed as the Liftgate Module (LGM) failure.

Key Fob does not function properly or it can not be programmed to the LGM.
Rear wiper, rear defog, or rear hatch/liftglass lock/unlock does not function or function properly.
Low tire pressure warning light comes on particularly in colder weather
No communication (Tech II) with the LGM.
Tire Pressure Monitor (TPM) Learn procedures will not complete properly.
In a study of LGMs returned under warranty, in the majority of cases, no problems were found with the LGMs. However, there are conditions that have been found when LGM replacement or reprogramming is necessary.

Recommendation/Instructions:
For each conditions listed above (in the Condition/Concern section), please follow the appropriate action below.

Key Fob does not function properly or it can not be programmed to the LGM. - See document #1857154 on RKE interference. If no interference is found and the Key Fob is still inop, try to program the keyfobs (see doc. # 665615). If an attempt to program keyfobs to the LGM is unsuccessful, try to learn the TPM sensors, if applicable (see doc. # 1876932). If the TPM learn sequence will not let you get past the horn chirp on the left front wheel and the keyfob would not learn, there is a good chance that the LGM has a bad resistor that is dropping out the RF circuit. If both of these conditions exist the LGM should be replaced, flashed with the proper calibration file (using SPS), and learn the keyfobs and TPM sensors learned. A further confirmation of this condition will be that the module has a date code of 120 thru 273 of 2006 (the date code can be viewed under module information for the LGM on the Tech 2). Otherwise, do not replace the LGM.
Rear wiper, rear defog, or rear hatch/liftglass lock/unlock does not function or function properly. - In a few cases modules have been found to have improper operating software/ calibration software combinations. This can cause:
• the rear wiper malfunction

• rear defog malfunction

• rear hatch/liftglass lock/unlock malfunction

• "no communication" with LGM message displayed on Tech 2

• indication (on the Tech 2) that the keyfob programmed but the keyfob continues not to function

• tire pressure sensor learn sequence will not give the double horn chirp to initiate the sequence

• abnormal battery drain

• If the calibration software number (look under LGM module information in the Tech II) is 10381248 this is the default manufacturer's calibration and will cause the conditions just described. To remedy this condition the proper calibration file must be flashed to the module using the Tech 2 and the Service Programming System (SPS). In some cases there has been a mismatch between the operating software and the calibration software. The condition may be able to be corrected by flashing the proper calibration to the module using the Tech 2 and SPS, If the calibration file that is listed in SPS is the same as the calibration file in the module, the problem is not with the LGM calibration. Do not replace the LGM.

Low tire pressure warning light comes on particularly in colder weather. - The TPM warning light illumination usually does not indicate that the LGM is malfunctioning. It may indicate that the Tire load range or tire pressure placard values are not set properly in the LGM. Check that the pressure settings match the placard values of the label on driver's door. The TPM warning light will normally illuminate when the tire pressure sensor sends a value that is 75% of the placard value plus 2 psi. For example, if the placard value is 35 psi then the light will normally go on when the pressure in the tire reaches 28 psi or less. Given that the tire pressure can drop approximately 1 psi for each 10 ° F temperature change, it is normal that the light may go on when starting out on a cold morning. The tire pressure can increase 2-3 psi when driving the vehicle, so the warning light may go out after the vehicle has been driven for a few miles. The tire pressures should be inflated to the placard values when the vehicle has not been driven for a few hours and tires are at the coldest temperature that the vehicle is likely to see in the driving season. If the tires are warm from being driven or the temperature is higher than the seasonal low temperature when inflated then they should be inflated to the placard pressure value but it may be necessary on a colder day to adjust the pressure up to the placard value to avoid the light coming on.
No communication (Tech II) with the LGM. - See item 2.
Tire Pressure Monitor (TPM) Learn procedures will not complete properly. - A low battery condition on the J-46079 Tire Pressure Monitor Diagnostic Tool (used in the TPM learn sequence) may be the cause of not getting the horn chirps at the wheels during the TPM sensor learn sequence. Check the battery life indicator level. If it is low, replace the batteries with a set of 100% Alkaline or rechargeable batteries( please note that: just one carbon battery in the tool, mixed with alkaline batteries, will restrict the current flow enough to cause problems with tool operation). Also, check if the tool has the most updated software. The correct software indicates a March 2006 date when the tool is turned on.This software update also improves the battery life and allows compatibility with rechargeable batteries. If a different J-46079 unit is available, try the procedure with the other tool to ensure that problem is not with the J-46079. In some cases when performing the TPM sensor learn sequence the DTC C0775 will be set in the fault history. This is not an indication that the learn sequence failed, unless the DTC has "failed/current" next to it after completing the procedure. Otherwise the DTC can be cleared and the TPM system functions properly. LGM should not be replaced.
Note: After learning tire pressure sensors, the vehicle must be driven for a short distance in order for the LGM to start receiving the tires pressure values. This can be verified by monitoring the tire pressure on the Tech2.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
 
#8 ·
Here's another TSB:

Document ID# 2011058
2007 Chevrolet TrailBlazer - 4WD


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Subject: Rear Liftgate Glass May Not Lock When Using Remote Keyless Entry (RKE)/Key Fob Transmitter/Door Lock Switch, Lifgtate Hatch or Liftgate Glass May Lock/Unlock When Rear Liftgate Glass Button Depressed #07-08-52-003 - (09/13/2007)



Models: 2005-2007 Buick Rainier

2005-2008 Chevrolet TrailBlazer, TrailBlazer EXT, TrailBlazer SS

2005-2008 GMC Envoy, Envoy XL, Envoy Denali

2005-2008 Saab 9-7X




--------------------------------------------------------------------------------
Do This

Reposition liftgate lock cylinder wave washer and adjust lock rod.
DO NOT replace the liftgate latch or actuator.


Condition
Some customers may comment on one or more of the following conditions:

• The rear liftgate glass may not lock when using the remote keyless entry (RKE), key fob transmitter or door lock switch unless the lock is pressed a second time.

• The rear liftgate or glass locks, but may be unlocked when the rear liftgate lock cylinder button is depressed.

• The rear liftgate locks but the liftgate glass may not lock.

Cause
These conditions may be caused by one or all of the following:

• The rear liftgate cylinder lock rod may be out of adjustment.





• The wave washer on the liftgate lock cylinder may be out of position with the cup side down.

• Excessive movement or slack in the lock rods at the liftgate bell crank assembly.
• The liftgate lock cylinder pawl may contact the rear liftgate glass latch when the lock cylinder button is depressed.

Correction
Important: Do Not remove the rear liftgate lock cylinder from the vehicle to perform this repair.

Reposition the rear liftgate lock cylinder wave washer and adjust the lock rod using the steps below.

Verify the customer's condition.
Open the liftgate.
Remove the upper liftgate garnish molding.
Remove the rear liftgate trim panel.
Remove the cylinder lock rod from the threaded lock rod retaining clip.
Tip
Place the tip of a screwdriver blade into the opening of the C-clip and slowly rotate the screwdriver to pry out the C-clip from the shaft. Then use needle-nose pliers to remove the C-clip.
Remove the C-clip from the rear liftgate lock cylinder push button and remove the wave washer.
Install the wave washer with the cup side up.
Position the wave washer with the curved edges of the wave spring parallel to the tabs on the lock cylinder shaft.
Important: Use needle-nose pliers to slightly squeeze the C-clip back into shape. Make sure the clip seated, you should feel a snap and hear an audible click.

Install the C-clip onto the shaft and in the slot using needle nose pliers. Then rotate the pawl several times to make sure the C-clip does not rotate. If the clip rotates then the clip is not fully seated.
Position the lock cylinder pawl to the full clockwise position.
Pull up on the cylinder lock rod to remove any slack in the bell crank.
Install the cylinder lock rod into the threaded lock rod retaining clip while removing any slack from the lock rod linkage.
Close the lock rod retainer clip.
Close the liftgate assembly.
Open the liftgate glass while keeping the liftgate closed.



Use the key fob to cycle the liftgate to the lock and unlock position while inspecting the rear liftgate pawl. The lock cylinder pawl should have clearance between the latch as shown above. If the pawl is contacting the latch, readjust the cylinder lock rod.
Verify that the customer's condition has been corrected.
Install the rear liftgate trim panel.
Install the upper liftgate garnish molding.
 
#9 ·
Mine would unlock the first time you pushed the button. Then if you closed the glass and relocked the truck it would not open unless the doors were unlocked UNTILL the rear gate was opened and closed.



I looked up the TSB # in the resource section TRAILVOY.COM. 2006 TB page 18 of the PDF, however I could not find the full text of the TSB.

http://www.trailvoy.com/docs/tsbs/2006TB-TSB.pdf
 
#10 ·
Just got the TB back from the dealer last night.

From work order,
"Cust states that rear glass hatch doesnt lock. Lock assembly weak not allowing glass to lock. Replaced liftgate lock assembly."

It works fine now. I mentioned that there might be a TSB when I dropped it off, but they didnt ask for specifics.

Thanks for all the helpful info guys,
Mike
 
#12 ·
Tailgate Question

Posted this a couple of days ago-cant find it. Just bought a 02 trailblazer LTZ.Been snowing ever since,went to open the tailgate and the top panel around the third light must have been lose but it got caught on the top of the roof and broke. Can anyone tell me how to get it off to replace. Panel on the top of the tailgate on the outside. DAVE MCLEOD
 
#14 ·
I just had this problem in my 07 TB. I adjusted the link as described but it still was flaky. Sometimes it would not lock fully, or sometimes, i would push in the glass release and it would pop the lock for the main hatch!

Anyway, noone else has posted this yet so here is what I did - lube all linkages. I was at my wits end with this problem and thought the levers were a bit hard to move, so i took out the wd40 and lubed all the joints.

It now works perfectly.

Thanks to those who posted pics, service bulletins and other tips!
 
#15 ·
Rear glass/hatch lock problems

I have an 07 Trailblazer and recently noticed a problem with the rear glass/hatch locks. When I lock the doors, whether with remote or button on door, it locks all doors and the hatch like it should. But if I push the glass release button the glass opens, the alarm doesn't sound, and the hatch unlocks. Then when I open the hatch, all doors unlock.

Has anyone else had this problem with all doors unlocking, and if so, how do you fix it?
 
#16 ·
Rear Glass Hatch Lock Fix

I popped part of the plastic panel off, and sprayed some silicone lubrication on the locking mechanism. It's working great now. The dealer wanted 120 bucks for the lock assembly plus 60 per hour for labor!

Try the easy solution before taking it to a dealer.
 
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