Sounds like you're on to it. It's funny, I was trying to relate your symptoms and test results to potential faults at the driver door as I had a gut feel that was a prime area for your problem. Have fun. Never hurts to clean and lube the other actuators and if you're rustproofing at the same time then that makes the minor effort of removing the other panels worthwhile.

Now if you can get it working with a replacement part then great, but I'm not sure I clearly understand the extent of the PO's butchered repair job. A 5-wire connector on the actuator? I thought it was a two wire connector on the pigtail from the actuator motor and a separate two wire connector (C79) on the pig tail from the door lock switch.

Ahhh, I'm having a vision -call it clairvoyant diagnosis. Some of the wiring broke in the hinge area. The original connectors were opened and the whole central locking harness in the door was pulled back to allow the broken section to be cut out and spliced (inside the car near the C144 connector block at the pillar if you're lucky). Now the connectors in the door didn't reach so all (male and female) got hacked off and 5 wires were spliced in to directly connect them to their components. More properly the door harness connectors should have been cut off leaving a pigtail and extension wires spliced in so the original connectors could be re-used. This also preserves wire colors at the ends of the harness making life easier for subsequent tracing. At that skill level I'd be pleasantly surprised if the splices were properly joined with a crimp or solder -more likely just twisted and taped. That would explain how that 5th wire came loose. If the splices are just twisted then be prepared for the ones at the hinge to pull open or the tape to come unraveled, possibly even shorting to something like chassis ground. I'm even having a vision of a PO frying the relay during subsequent testing at which point the person probably swore off the job, sold the car, bought a Toyota and lived happily ever after. The end. :=)

Post back and give me a brief summary of how you make out.
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Dave -940's, prev 740/240/140/120 You'd think I'd have learned by now