Power door lock issue

Discussion in 'Audio & Electronics' started by Matt B, Oct 23, 2018.

  1. Matt B

    Matt B TYF Newbie

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    I'm currently troubleshooting a power door lock issue on my ‘98 Yukon (4dr). The driver side door and rear cargo door will not lock/unlock. I’ve tested both actuators; they are good. I’ve checked continuity of the door harness; it is good (no broken wires). Power for both the door (and I’m guessing the rear door harness) comes down through the cowl around the hood release handle. I have 12v on the grey wire, nothing on the tan wire coming back from the relay. Same issue in the back, at the rear doors. Does anyone know where these wires tie together, before I start ripping out the dash? According to the schematic, all of the tan wires (for every door actuator) are paralleled together, and all of the grey wires (for every door actuator) are paralleled together after the relay. I believe the wires for the rear cargo doors may run down the driver side sill (found a harness under that kick panel at the hood release, wires tested the same). All of the other three passenger door power locks work fine. Thanks in advance.
     
  2. Doubeleive

    Doubeleive Supporting Member

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    first thing I would try is replacing the relays there fairly cheap even though they may be working they may no longer be 100%, it's worked for other people before.
     
  3. east302

    east302 Full Access Member

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    Here are the diagrams for a 1998. I found conflicting diagrams for connector C302, which looks to be what goes to the cargo doors. One diagram shows it at the driver A-pillar, the other at the B-pillar. The variance may be for two versus four door Tahoes.

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  4. trevcda

    trevcda Full Access Member

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    I don't know which model/year you have, but if you have barn doors, all of the wiring for the doors goes through contact pins/pads between the door and the body. a) they will not pass power when they are open and b) they can get dirty enough that they may not pass power when closed. I should know better by now, but I still get tripped up by the first one if I haven't been working on it in while. As far as the driver's door goes, I may be thinking of another car, but doesn't the drivers door have the ability to unlock separate from everything else? It may be on a slightly different circuit, as in first press of the remote unlocks the driver's door and the second unlocks everything else.
     
  5. trevcda

    trevcda Full Access Member

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    I verified that My 1999 OBS does do this. So you may be looking at two different, but closely related circuits here.
     

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