Planning the next
AO Silver Member
Join Date: May 2007
Location: United Kingdom
If you have a multimeter, unplug the 5 way plug at the lock and measure pins 1 and 2 when the locks operate. The wire colours should be Grey and Yellow. You should get a brief +12v either locking or unlocking and -12V the other way. If your meter doesn't do negative volts, turn the probes around. If you don't have a multimeter, connect a low* wattage bulb to pins 1 and 2. It should light up when the controller tries to lock and unlock the doors.
If the test is a success, I'd be looking to replace the lock motor.
If you don't get evidence of +12v at the connector, you have a wiring fault somewhere.
* the 5 watt bulb from the puddle light would do the job as the door card is already off. Make sure the bulb works before using it to test!