I have an old (2000) Ford Ranger truck. At around 2008 the electric door lock actuators started failing. First the passenger side and later the driver’s side. The problem manifested it self in only one actuation being possible until after a few minutes rest between actuation attempts. Their failure was gradual until the passenger side was totally inoperative. I was suspicious of electrical resistance because each time I clicked the remote the actuator’s action became weaker until it would not function until given a few minutes to “cool down”. Since both locks were failing I suspected oxidation in the contacts where the wiring passes through the firewall. Upon investigation, it was very difficult to get to the pass-through so I decided that I’d replace the worst actuator, the one on the passenger side.
Yesterday I replaced the passenger side actuator with a Chinese clone purchased on eBay. Replaces part 6L3Z25218A43AA. The job is a real pain because of the part’s inaccessible, hidden location. A mirror, flashlight and much patience are required. It took me over an hour of fumbling, squinting, cussing and groping to get it replaced.
Anyway, I always like to see how things work so I had to crack the old one open. Photos are below. Before I opened it I applied 12VDC to the external contacts but it was dead. The power is fed to the motor via silver colored contacts that slide into sockets in the motor (see photo below). Opening the unit would wipe clean the contacts as they were removed from the contacts so further electrical testing, while done, was of little diagnostic value.
The motor is functional with a 12VDC 1.5A power supply applied directly to the motor’s contacts. Since both actuators started failing near the same time, about eight years, the cause of failure appears to be a design flaw. I suspect the culprit was oxidation or dirt but given how well sealed the unit was, oxidation is more likely the cause than was dirt. The connection snaps together with a positive click so it wasn’t inadequate pressure of the contacts.
Next, I replaced the driver’s side door lock actuator and since I now what I was doing and had the most successful tools arranged, the job only took me 30 minutes.