is it possible there is a "lockout button " or switch that has been activated-either in the glove box, on the floor next to drivers seat(near door opening) or even inside the center console where u would rest your elbow?? THIS BUTTON/SWITCH would prevent key/fob from unlocking liftgate. ALSO CHECK to make sure that ther is nothing caught(fabric/clothes) near the LATCH WHERE LIFTGATE ENGAGES. this can definitely cause a problem!
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The endgate/liftgate can be locked or unlocked by operating either one of the front door lock switches, your's doesn't do this ?
Endgate/Liftgate
Once the vehicle doors have been unlocked, the endgate/liftgate can be opened by using the handle mounted to the exterior of the gate. The endgate/liftgate can be locked or unlocked by operating either one of the front door lock switches, or by pressing the Lock/Unlock button on the key fob. The endgate/liftgate lock and unlock functions operate in conjunction with the rear doors.
None < LGM - liftgate control module inside the lift gate does .
Rear Wiper/Washer System Components
The rear wiper/washer system consists of the following components:
• Rear window wiper motor
• Rear washer pump
• Rear wash relay
• Rear wiper/washer switch
• RR WIPER Circuit Breaker 15A / ENDGLASS REG Circuit Breaker 30A
• WASH 20A fuse
• Body control module (BCM)
• Liftgate control module (LGM) / End gate module (EGM)
Your best bet , take it to a qualified repair shop. You have no idea of the complexity of these system's . Communication network between modules etc..... Could have DTC'S diagnostic trouble code's stored in the liftgate control module . An auto parts stores can not read these codes .
Power Door Lock Operation
The power door lock switches are integral components of the DDM and PDM. The switches are two position normally open rocker switches. When placed in either the lock or unlock positions, the switches provide a direct input to the DDM or PDM. The DDM or PDM monitors these inputs and sends a Class 2 message indicating a change in the switch's respective position. Modules which activate the power door lock motors receive the Class 2 message and activate the motor in the appropriate direction to lock or unlock the vehicle's doors and liftgate. The modules which activate the power lock motors are:
• DDM (driver door lock actuator).
• PDM (passenger front door lock actuator).
• BCM (both rear door lock actuators).
• LGM (liftgate door lock actuator).
The DDM, PDM and LGM are directly connected to the respective door lock actuator through the door lock motor lock and unlock circuits. Once a door lock or unlock request has been received, the module will supply battery voltage to one side of the actuator and ground the other causing the doors to lock or unlock.
The rear hatch locking is computer contolled .
The BCM also runs diagnostics on the liftgate lock relay control circuit and will set DTC B3825 as current and also send a Class 2 message to the DIC. The DIC will display REPLACE LIFTGATE FUSE to inform the driver that a fault has been detected in the liftgate lock circuit and that the liftgate is not locked. Faults that will set the DTC and cause the DIC to display the message could be any of the following:
• An open ECC fuse
• An open or short to ground in the liftgate lock relay battery positive voltage circuit
• A faulty liftgate lock relay
• An open or short to ground in the liftgate lock relay control circuit
• A short to ground in the liftgate lock actuator lock control circuit
• A faulty BCM
The liftgate lock relay supply and coil sides receive a constant voltage through the battery voltage supply circuit and the ECC fuse. The normally closed contact is connected to ground and the control side is connected to the body control module (BCM). A lock function will occur when a door lock switch activation, keyless entry lock transmission, auto door lock function or a liftgate lock function has been received by the BCM. The BCM will then ground the control side of the liftgate lock relay. This energizes the relay and allows voltage to be applied to the liftgate lock actuator lock control circuit. Since the other side of the liftgate lock actuator is connected to the normally closed contacts of the door unlock relay to ground, the liftgate will lock. When an unlock function occurs the BCM will ground the control side of the unlock relay and the rear doors and liftgate will unlock.
The power door lock system consists of the following components:
• The driver door module (DDM)
• The passenger door module (PDM)
• The body control module (BCM)
• The driver information center (DIC)
• The rear door lock switch
• The door lock relay
• The door unlock relay
• The liftgate lock relay--utility vehicles with liftgate only
• The reversible door lock actuators in each of the doors and liftgate
• LOCKS 20A fuse (rear lock/unlock relay supply voltage)
• ECC 10A fuse (liftgate lock relay supply voltage)
If i were to guess i would say you mite need a new lock actuator , but i don't guess . You could take the hatch inside panel off an check for B+ voltage for the lock actuation as someone pushes the switch . Or have it checked for codes .
There is a known TSB for this....
#07-08-52-003: 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 - (Sep 13, 2007)
Subject: Rear Liftgate Glass May Not Lock When Using Remote Keyless Entry (RKE), Key Fob Transmitter or Door Lock Switch, And/Or Liftgate Hatch Or Liftgate Glass May Lock Then Unlock When Rear Liftgate Glass Button is Depressed (Reposition Lock Cylinder Wave Washer and Adjust Lock Rod)
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
Don't 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.
#07-08-52-003: 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 - (Sep 13, 2007)
Subject: Rear Liftgate Glass May Not Lock When Using Remote Keyless Entry (RKE), Key Fob Transmitter or Door Lock Switch, And/Or Liftgate Hatch Or Liftgate Glass May Lock Then Unlock When Rear Liftgate Glass Button is Depressed (Reposition Lock Cylinder Wave Washer and Adjust Lock Rod)
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
Don't 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.
To unlock the liftgate, press the unlock button on the Remote Keyless Entry (RKE) transmitter twice or use the power door lock switch. To lock the liftgate, press the lock button on the RKE transmitter or use the power door lock switch. The liftgate does not have a key lock cylinder. To open the liftgate, pull up on the handle located in the center of the liftgate. When closing the liftgate, use the molded handles to pull the liftgate down. Push the liftgate closed until it latches.
This solution applies to models: 2002-2007 Chevrolet Trailblazer, Trailblazer EXT and Trailblazer SS 2004-2007 Buick Rainier 2002-2007 GMC Envoy, Envoy XL, and Envoy Denali 2002-2004 Oldsmobile Bravada 2005-2007 Saab 9-7x
Condition/Concern: Rear liftgate glass will not lock when using the key fob or door switch unless the lock button is pressed a second time. All other doors will lock normally. This could be the result of the liftgate glass lock rod not adjusted correctly. This lock rod travels from the liftgate lock actuator to the glass release push-button cylinder.
Recommendation/Instructions: Remove the inside rear liftgate trim panel. Disconnect the threaded lock rod clip at the end of the push-button glass release and rotate this clip 1 complete turn at a time making the lock rod longer. This will be the only threaded lock rod visible when the trim panel is removed and the liftgate is raised. Note: For the rear glass to release, the rear liftgate latch must be in the closed position. For test purposes only, this latch can be made closed to make this lock rod adjustment.
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.
Take the liftgate inside panel off an check the wiring , connections etc.... rear door hatch lock repair GMC Chevrolet chevy tahoe lift gate not opening
The liftgate will lock any time the vehicle is shifted out of park on vehicles equipped with an automatic transmission and at vehicle speeds exceeding 5 kph with manual transmission. This happens in conjunction with auto door locks if enabled or independently of auto door locks if the feature is disabled. This ensures that the liftgate is locked anytime the vehicle is shifted out of park or when the vehicle is in motion.
The liftgate lock relay supply and coil sides receive a constant voltage through the battery voltage supply circuit and the ECC fuse. The normally closed contact is connected to ground and the control side is connected to the body control module (BCM). A lock function will occur when a door lock switch activation, keyless entry lock transmission, auto door lock function or a liftgate lock function has been received by the BCM. The BCM will then ground the control side of the liftgate lock relay. This energizes the relay and allows voltage to be applied to the liftgate lock actuator lock control circuit. Since the other side of the liftgate lock actuator is connected to the normally closed contacts of the door unlock relay to ground, the liftgate will lock. When an unlock function occurs the BCM will ground the control side of the unlock relay and the rear doors and liftgate will unlock.
The BCM also runs diagnostics on the liftgate lock relay control circuit and will set DTC B3825 as current and also send a Class 2 message to the DIC. The DIC will display REPLACE LIFTGATE FUSE to inform the driver that a fault has been detected in the liftgate lock circuit and that the liftgate is not locked. Faults that will set the DTC and cause the DIC to display the message could be any of the following
Power Door Locks Inoperative - Endgate/Liftgate
Schematic Reference: Door Lock/Indicator Schematics
Connector End View Reference: Power Door Systems Connector End Views
1
Did you perform the Diagnostic System Check - Vehicle?
YES - Go to Step 2
NO - Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2
Activate the door lock switches to the lock and unlock positions.
Do both rear passenger doors lock and unlock?
YES - Go to Step 3
NO - Go to Power Door Locks Inoperative
3
Did the liftgate lock actuator lock and unlock?
YES - Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
NO - Go to Step 4
4
Disconnect liftgate door lock actuator.
With a test lamp connected to a good ground, probe the door lock actuator lock circuit at the door lock actuator harness connector.
Activate a door lock switch to lock position.
Does the test lamp illuminate?
YES - Go to Step 5
NO - Go to Step 7
5
With a test lamp connected to a good ground, probe the door lock actuator unlock circuit at the door lock actuator harness connector.
Activate a door lock switch to unlock position.
Does the test lamp illuminate?
YES - Go to Step 6
NO - Go to Step 8
6
Inspect for poor connections at the harness connector of the door lock actuator. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?
YES - Go to Step 10
NO .. Go to Step 9
7
Repair the open door lock actuator lock circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
YES - Go to Step 10
--
8
Repair the open in the door lock actuator unlock circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 10
--
9
Replace the liftgate door lock actuator. Refer to Door Lock Actuator Replacement in Body Rear End.
Did you complete the repair?
Go to Step 10
--
10
Operate the system in order to verify the repair.
Did you correct the condition?
System OK
Go to Step 2
×