Accessories such as electric door locks, rear hatch lock, auto garage door openers, intermittently do not operate. the door locks will open 2 doors and then open 3 doors, can hear the hatch try to open but seems like power is lost. batteries are fully charged and operating at proper levels

remove rear panel and check latch for damage or linkage disconnect --also check electrical connections to other components

Rear hatch is locked or unlocked with a key. (if equipped) • To open the rear hatch, insert the key into the lock, turn it to the unlock position and pull up the rear hatch by pressing the handle (DOOR). You can also lock/unlock the latch (but not release it) with the central door lock system. • If unlocked, the rear hatch can be opened by pressing the handle (DOOR) and pulling the hatch up. • To close the rear hatch, lower and push down the rear hatch firmly. Make sure that the rear hatch is securely latched.

rear door hatch lock repair GMC Chevrolet - YouTube

? 4:26
https://www.youtube.com/watch?v=QS3PMhGgyAg
Apr 5, 2014 - Uploaded by auto resource
2002 Yukon, rear hatch lock not locking. ... rear door hatch lock repair GMC Chevrolet. auto resource ... chevy tahoe lift gate notopening - Duration: 2:12. ... A Method how to unlock your car in 10 seconds :) - Duration: 0:35.

chevy tahoe lift gate not opening - YouTube

? 2:12
https://www.youtube.com/watch?v=xU6ybiY3F4I
Sep 1, 2010 - Uploaded by 76bluemoon
Back lift gate/glass would not open or release. Even when unlocked with the key fob or the unlock switch on the drivers/passenger door. ... How To Install Replace Rear Lift Gate handle 2002-09 GMC Envoy Chevy Trailblazer ...

There are actually three relays , an there are controlled by the BCM - body control module !
When a door lock switch is activated in the lock or unlock position the BCM will receive a voltage signal on either the door lock switch lock or unlock signal circuits.
The BCM, upon receipt of a lock switch lock or unlock signal, will switch the appropriate lock relay control circuits to battery positive voltage. This will energize the appropriate lock or unlock relays. The relay will supply voltage to the door lock actuator lock or unlock control circuits to one side of the lock actuator. Since the opposing side of the lock actuators are connected to ground through the other lock actuator control circuit and the normally closed contacts of the lock or unlock relay, the doors and liftgate will then lock or unlock appropriately.
Three relays are used to operate the locks. DRV DR UNLCK relay, PASS DR UNLOCK and DR LCK relay. This is done to isolate the driver door lock actuator so it can be unlocked by itself using the keyless entry transmitter.
Rear Hatch/Gate Description and Operation
The liftgate can be opened by operating the switch on the instrument panel. Battery voltage is supplied to the liftgate actuator through the body control module (BCM). The BCM will pulse the liftgate actuator when a release input is received through the key fob, or the instrument panel switch.
Door/Lift gate Latch Assembly

1. Install a 20-A fused jumper wire between the control terminal 3 and 12 volts. Install a jumper wire between the ground terminal 2 and ground.
2. Verify the actuator turns on & off.

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If the function does not perform as specified, replace the applicable door latch.

My Envoy does that too. I figured out the unlock automatic setting on my keys had to be pushed twice!

first is diagnosis.
you examine and test it. to see if its electrical or mech. failure.
and once discovered that follow that to logical conclusions.

IN SIDE THERE IS A CIRCLE LOW BY HANDLE POP OPEN AND ACCESS LOCK BYPASS, IT WILL OPEN DOOR, YOU CAN GET A NEW REAR LOCK ACTUATOR! REMOVE DOOR PANEL 2 BOLTS EASY FIX . DOOR WILL NOW OPEN!!

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

1) Unlock all doors from driver's door while it is open. The driver's door is the only door to remain open during this process! 2) Turn the key from OFF to RUN 8 times within 10 seconds, with the eighth turn ending in RUN. All the doors will lock and unlock if program is successful. 3) Turn key OFF and remove key from ignition. Within 20 seconds, press any button on the remote. (Press sliding door or rear hatch and it will open!) 4) If door locks do not respond, wait several seconds and press button again. If doors still fail to respond, try repeating steps (1-3).