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.
Remove the old door lock relay.
The mechanical latching relay only requires it s coil to be momentarily energized to change and maintain the opening or closing of it s contacts.
Using a pair of needle nose pliers pull out the old relay.
That s where most wire breaks occur.
If your alarm or keyless entry has positive outputs only you will have to connect the other side of the coils to ground and connect your outputs as shown.
For those located under the dash in the middle of the cab behind 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 a power door lock wiring diagram for a 2009 chevrolet malibu.
Locate the door lock relay.
Here s how a body control module power door lock system works.