Driver door won't unlock with power switch

[skahide]

1998 Yukon. Driver door won't unlock with power unlock switches (neither driver nor passenger switches). Lock works flawlessly. All other doors work flawlessly.

Functions fine with key from outside.
Functions fine when you slide the lock tab up and down.
No issues with any binding, or movement within door mechanics.
Replacement actuator has same results, even when not connected to rod.
Replacement driver door switches has same results.

Edit: I have the RPO code for keyless entry but do not have any fobs. If that matters.

Any ideas what it could be?

 

[east302]

Replacement actuator has same results, even when not connected to rod.

So the actuator doesn’t respond even with the rod disconnected?

Check for voltage on the tan wire at the actuator connector when the unlock switch is depressed. Check using the chassis and also the gray wire as ground. It’s reversed for lock - gray is voltage, tan is ground.

If that doesn’t work, connector C209 should be accessible by removing the kick panel and pulling the connectors out a bit. Those are the wires that come from the door through the rubber bellows into the cab. See how it looks.

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[skahide]

So the actuator doesn’t respond even with the rod disconnected?

Correct. With replacement actuator plugged in to wire harness but not connected to anything else, it still will lock but not unlock.

I will look through all those suggestions tomorrow. Thanks!

 

[skahide]

Check for voltage on the tan wire at the actuator connector when the unlock switch is depressed. Check using the chassis and also the gray wire as ground. It’s reversed for lock - gray is voltage, tan is ground.

If that doesn’t work, connector C209 should be accessible by removing the kick panel and pulling the connectors out a bit. Those are the wires that come from the door through the rubber bellows into the cab. See how it looks.

Finally got to look into it. No voltage to tan wire when using chassis or gray wire. C209 (and all wires in that area) look great.

 

[east302]

Check at C209 then, tan and gray pins. If the other locks unlock, then the loss is somewhere between splice S258 and the actuator (red highlighted line in diagram below). If you have voltage at 209, then the issue is between that connector and the actuator.

Not entirely sure where splice 258 is, but it’s somewhere near the convenience center at the harness that goes to C210.

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[skahide]

Check at C209 then, tan and gray pins. If the other locks unlock, then the loss is somewhere between splice S258 and the actuator (red highlighted line in diagram below). If you have voltage at 209, then the issue is between that connector and the actuator.

Earlier I unplugged C209 and found continuity from C209 and the actuator plug in both the tan and gray lines, separately.

So I need to check the continuity of the tan wire between the C209 plug and the S258?

I need to have someone pressing the unlock button from the passenger door while I have my multimeter grounded to the chassis or gray wire, and probing the tan wire at the C209 connector?

Also, could this be the door lock relay, or would that effect all the door unlock functions?

I'm sorry. Electrical isn't my strength.

 

[east302]

Yes. That’s the way I see it provided that the other actuators unlock and you have no voltage at C209 tan when the unlock switch is pressed.