Intermittent problem with rear lift gate on 2006 Chevy Tahoe Z71. Went to lock vehicle and noticed that the horn did not sound. Checked all doors and could not locate any open. Have not had the lift gate opened lately. When I got back in, the display by the steering wheel stated lift gate was open. Went and checked and it looked like the right side was unlocked, up the left side was not. Tried to lock and unlock and nothing would happen. Also, the glass back would not open either. Any suggestions? I have noticed this once or twice, but it always corrects itself.
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
SOURCE: 2006 chevy tahoe liftgate won't open when keyless remote unlocks
check fuse first always, then check connections fron rear gate to body.
SOURCE: rear glass will not open. push button and makes
2000 Chevy Blazer 4 door with pop up glass and drop down gate. I experienced this exact problem 4 years ago. The glass unlock actuator inside the drop down hatch has a small plastic piece connect to it. This piece pushes the glass unlock mechanism. In order to temporarily unlock, you must pull the carpeting piece down and located in the center is an access hole where your can depress the unlock mechanism from inside, until you find a replacement piece. I recommend the pick and pull lots where you can find a similar make and model blazer with the drop down gate. I was able to get the piece and actuator (just in case) for $5. You will have to disassemble the gate in order to replace the plastic piece which is easily removed from the actuator, but cannot be fixed with glue, even with crazy glue. Have a excellent day and pass it on!
SOURCE: 2008 Tahoe: The automatic back lift gate on my 2008 Tahoe stop...
I found this URL on internet http://www.chefseattle.com/blog/site-news/suburban-rear-liftgate-wont-unlock-how-to-fix/ If your vehicle is similiar maybe it can help.
SOURCE: Lift gate door will not lock or unlock
Check out the following link, it is a step by step process to getting the fix...
http://www.chefseattle.com/blog/site-news/suburban-rear-liftgate-wont-unlock-how-to-fix/
?€¢
An open or short to ground in the lift gate lock relay battery positive voltage circuit
?€¢
A faulty lift gate lock relay
?€¢
An open or short to ground in the lift gate lock relay control circuit
?€¢
A short to ground in the lift gate lock actuator lock control circuit
?€¢
A faulty BCM
To open the lift gate manually, use the door unlock switch located
on the drivers door. This should unlock the lift gate as well. Go to the lift
gate and lift the handle to open the rear gate.
Your power lift gate is computer controlled. Sometimes there will
be a faulty input sensor or part that will show the incorrect data to the computer,
therefore the computer will not go through its normal functions.
In most cases its the problem of lift gate latch assembly.
To get it tested and confirmed there is a troubleshoot guide
provided by the service center. To perform this troubleshooting guide you will
require a scan tool to diagnose the exact problem.
the troubleshooting procedure is as follows:---
Please use the following information below when diagnosing an inoperative
lift gate. Disconnect the connector at the lift
gate latch assembly. With the lift gate latch connector disconnected, the 3
signals for the ratchet, pawl, and the sector should be inactive on the scan
tool.
Install a 3A fused jumper wire between each signal circuit
terminal (for the pawl, sector, and ratchet) and the ground circuit terminal 2.
Monitor the scan tool as each individual circuit is jumped to ground, the scan
tool should read "active".
If either tests above fails, check the wiring for the signal
circuits, low reference circuit, or try a power lift gate control module from a known good vehicle. If both tests above pass, monitor the internal switch inputs in
the lift gate latch assembly for proper operation.
3. A) with the lift gate in the open position, the ratchet and the
pawl should read "active" and the sector should read
"inactive"
B) With the lift gate in the secondary latched position, the pawl
should read "Inactive" and the ratchet and sector should read
"active"
C) With the lift gate fully closed, the pawl, ratchet, and the
sector should all read "inactive".
4.If one of the internal lift gate latch assembly switch inputs
are not reading correctly in one of the positions above and the vehicles passes
test 1 and 2 above. Replace the lift gate latch assembly.
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.
This should help you.Thanks.Helpmech.
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