Tailgate not locking with fob

[vikki]

Has anyone has this issue? 2021 Jeep Gladiator

The tailgate has quit locking with the key fob. The doors lock, but the tailgate does not lock. I have to lock it with the key. All doors AND the tailgate unlock with the key fob. Any suggestions?

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[DylanM]

Does the tailgate lock when you use the button located in the doors?

 

[vikki]

No, but it unlocks with those buttons. The only way that I can lock it is with the key.

 

[DylanM]

Place your hand on the tailgate near the lock and press the lock button on the fob. Can you feel and/or hear the tailgate lock motor actuate? If yes, then remove the access panel on the inside of the tailgate and take a look at the handle mechanism to determine what has come loose or disconnected. If no, then either the lock motor has failed or there's a fault with the BCM.

 

[Dilly’S Willy]

When did they put a key slot on the tailgate? Am I blind?

Pretty sure I've caught myself making a joke to myself about "man I hope I never have to use the tailgate with the cover if the electric lock fails" haha.


But to offer insight, take a look at the wiring diagram for the tailgate and unplug the connector for that harness, then test the wire that activates the lock with a smaller 12v source (a wifi router plug has enough power to actuate the motor for example).
- Test using this method at your own risk as I have NOT tried this on a JT. It works on older vehicles, but they didn't link EVERYTHING through the CANBUS.

 

[vikki]

Does the tailgate lock when you use the button located in the doors?

Place your hand on the tailgate near the lock and press the lock button on the fob. Can you feel and/or hear the tailgate lock motor actuate? If yes, then remove the access panel on the inside of the tailgate and take a look at the handle mechanism to determine what has come loose or disconnected. If no, then either the lock motor has failed or there's a fault with the BCM.

Does the tailgate lock when you use the button located in the doors?

Place your hand on the tailgate near the lock and press the lock button on the fob. Can you feel and/or hear the tailgate lock motor actuate? If yes, then remove the access panel on the inside of the tailgate and take a look at the handle mechanism to determine what has come loose or disconnected. If no, then either the lock motor has failed or there's a fault with the BCM.

 

[vikki]

We have had the cover off and can see the mechanism unlock when we use the remote or door buttons. But, they don’t lock it- the only way to move the mechanism to the locking position is with the key in the tailgate.

 

[vikki]

Place your hand on the tailgate near the lock and press the lock button on the fob. Can you feel and/or hear the tailgate lock motor actuate? If yes, then remove the access panel on the inside of the tailgate and take a look at the handle mechanism to determine what has come loose or disconnected. If no, then either the lock motor has failed or there's a fault with the BCM.

 

[vikki]

What would cause the mechanism to unlock but not lock is confusing, it is not bound up, just only working one direction (unlocking) unless you use the key.

 

[Dilly’S Willy]

What would cause the mechanism to unlock but not lock is confusing, it is not bound up, just only working one direction (unlocking) unless you use the key.

So I was blind about the key slot, my b.

Did you check the wiring like I suggested?

 

[DylanM]

The door lock motors and the tailgate lock motor are all controlled by the body control module (BCM). When you press a button on your fob or one of the door buttons, that sends a signal request to the BCM to lock or unlock. In response to the signal request the BCM sends voltage to each lock motor to operate it.

Looking at the wiring diagram attached below, we see that each lock motor has its own dedicated two wire circuit running between it and the BCM. Based on this and the fact the diagram does not show any motor being grounded, we can infer that the BCM controls the direction of each lock motor's movement by switching the polarity of the circuit. Put another way, the BCM sends power on wire one and grounds wire two to move the motor to unlock and sends power on wire two and grounds wire one to lock it.

Since the tailgate lock motor does operate to unlock, it's fairly safe to say the wiring between the BCM and tailgate lock motor is good since both wires are needed to function. So either the tailgate lock motor is faulty, or the BCM isn't sending the reversed polarity voltage to the motor to lock it when requested to do so.

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