Should you need to add relays for a 3 wire negative type b door lock system just change both normally open terminals 87 from 12v to ground.
Power door lock relay wiring.
For those located under the dash in the middle of the cab behind the stereo.
Using a pair of needle nose pliers pull out the old relay.
That s where most wire breaks occur.
Find the door lock relay.
Remove the panel that covers the area under the stereo.
If the relay and switch are working properly but you re not getting power and ground at the door lock actuator check the wiring harness in the hinge area of the door.
Here s how a body control module power door lock system works.
Remove the old door lock relay.
Locate the door lock relay.
Here s a power door lock wiring diagram for a 2009 chevrolet malibu.