Power door locks LOCK but don't UNLOCK???

Asked by Oct 25, 2016 at 10:29 PM about the 1998 GMC Suburban C1500

Question type: Maintenance & Repair

I have a GMC C1500 Suburban  2WD V-8-5.7L 1998 and am having issues
with all the locks (except drivers door) being able to Lock thru switch and Key
Fob but none of them unlock (again except for drivers door).  I'm a newbie so
did the first thing I saw on you tube and purchased a door lock actuator and
replaced on passenger side.  It did the same thing.  Now the passenger back
door doesn't do either??? I've read that sometimes they all go out and to
replace them all but found somthing strange with the wiring on the passenger
door that made me wonder.  I've seen diagrams that show the wire going
from the actuator to the lock switch mechanism, but mine go somewhere else
and different colored wires are coming from somewhere else and plugged
into the switch instead??? It was done recent since the duck tape is fairly
new compared to other wires that you can tell have been there for 20 yrs
untouched.  What to do?? The wires from actuator are light brown and grey
and the light wires are orange and white.  The pic is the door switch with A
and B being empty, C and D have white and orange and brown is in the back
connected to K I think and no grey. The only actual wires connected to the
switch from the door is the Power Window and it's been spliced with the
incoming Grn wire and connects to switch. ???

2 Answers


You'll need to get a wiring diagram for the door lock system. Sounds like a previous owner rigged it to work, kinda. I once had a car that the power windows had been wired to the left rear cigarette lighter. This allowed power to "back feed" through the system to make the windows work. The original problem was a bad window relay. HTH. -Jim

I've had it for many years and my mom had it before me. Naa what happened I think is I was having problems with my battery staying charged and took it to a garage that said the security alarm was draining the battery and so they removed it. I didn't know any better. I did get a diagram and in it shows the actuator going directly to the power lock mechanism and then other wires going out from there to fuse box I'm guessing.

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