The driver's door power lock on my 88 Bronco is not working. When I pulled the plug on the actuator only one side appeared to have any power. When I tried a new actuator it was still not functioning. The new unit worked fine on the other door. I am thinking that there may be some bad wiring to the driver's door, even if there is voltage perhaps there isn't enough amps flowing. I traced the wires to in front of the coolant and washer tank, where the relays are. I am thinking of rewiring from the relays back to the driver's plug so that I can keep the plug connections. I could find the wiring point where the wires split and go to the passenger's and rear gate, but the route from the relays to the driver's door is pretty much a straight shot. Anyone have any other ideas to check first or suggestions?
Thanks.

 

Make two individual, 15 foot, fused 15 amp (each one is 15 amp) test leads with ->small<- alligator clips. Apply to the lock to see if it locks or unlock. That is the first step I take when working with the windows and locks before I start troubleshooting. It helps determine if the fault is the switch, wiring, motor, or actuator.

 

The problem ended up being one wire to the door lock actuator and another wire to the lock button. Since I couldn't find the wire junction in the cab, I traced the wires to the relays just in front of the coolant bottle. I patched the wires from this point, following the existing wiring to the door switch and lock actuator. All work good now.