Drivers door will lock with ‘keyless entry’ or switch but won’t unlock

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I recently purchased a 1999 Yukon. The drivers door will lock with the power door lock switch and with the keyless entry remote, but won’t unlock with either. The lock mechanism slides freely when moved manually. All of the other door locks function normally.

I assumed it was the door lock actuator and replaced it, yet the problem still exists. I’m showing 12 volts at the actuator when the door lock switch is pressed, but only 2 volts when the unlock switch is pressed. Any suggestions?

 

[Doubeleive]

I recently purchased a 1999 Yukon. The drivers door will lock with the power door lock switch and with the keyless entry remote, but won’t unlock with either. The lock mechanism slides freely when moved manually. All of the other door locks function normally.

I assumed it was the door lock actuator and replaced it, yet the problem still exists. I’m showing 12 volts at the actuator when the door lock switch is pressed, but only 2 volts when the unlock switch is pressed. Any suggestions?

maybe the door lock relay needs to be replaced? that has solved some peoples problem before

 

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My understanding is that a bad relay affects all doors not just one. Could a bad relay affect just one door?

I guess it’s worth a shot. Thanks for your input.

 

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Tried a new power door lock relay. No change...

Any other suggestions?

 

[Sean James]

You gotta start tracing wires, that's a tough one. You have replaced all the usual suspects, so it's got to be a wiring issue...ground, short, open. The wires that run from the body and through the rubber into the door must bend every time you open and close the door. Sometimes the wire can break inside the rubber from "work hardening" the copper wire. You can try leaving the door open at different positions to see if you get it to work, this will be an indication, but not always. You can try running jumpers. A pain in the rear. I had a break inside a wire at the door/frame transition, and the wire insulation was still intact, took me years to find it. Maybe youtube search, etc.