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Power Door Locks

If your factory door lock actuators are weak or dead, there is hope. The actuator is operated by a small electric motor and a lot of gear reduction. The motors tend to burn out after several years. Fortunately, a drop-in replacement motor is readily available and affordable.

I am assuming that you have already removed the actuator from your car door. This is not a complicated procedure. You just need a Torx bit and a lot of patience.

Use a small Philips screwdriver to remove the screws holding the access cover to the actuator. You will probably see some black dust around the electric motor. This should be carbon which has worn off of the brushes. This is not necessarily a symptom, but doesn't help.

Carefully pull the motor from the plastic actuator housing. I am showing you the driver's and passenger's side actuator so you can see the wiring. Pay attention to the location of the polyfuse, relative to the vents in the side of the motor. Use a soldering iron to de-solder the polyfuse lead and blue wire from the motor. There should be a black rubber sheet wrapped partway around the motor. Peel this off and save it.

Now you need to make a custom tool. I used a stamped steel "wrench" from a certain Swedish furniture company. You could also use a cheap flathead screwdriver. Cut a 2mm notch in the end of the tool. This will help you pry the worm gear off of the motor shaft.

Put the old motor in a vise. Don't worry about crushing it as you only need to reuse the worm gear. Use a flathead screwdriver and your custom tool to carefully pry off the gear.

Here is your new motor, a Mabuchi FK-280PA. The shaft should be 2mm in diameter and about 10mm long. The length can be plus or minus a couple mm and still work fine. You can buy these motors for a few dollars on E-bay from a variety of sellers. The are popular for use with model trains. In this case, the motor came with an incorrect gear attached.

Do not attempt to pry the gear off as you will probably damage the motor. Use a pair of pliers to pinch the gear teeth and break them. The gear should slide right off now.

Now you need to tap the old worm gear onto the new motor. You must support the rear of the motor shaft. Use a metal plate or something else that the shaft won't sink into. Lightly tap the worm gear onto the shaft using a plastic hammer or screwdriver handle. You don't want to damage the end of the brass gear. Don't expect the gear to bottom out. Check the fitment of the motor in the actuator housing to determine if the gear is on far enough.

Solder the polyfuse lead and blue wire onto the new motor. Pay attention to the location of the polyfuse relative to the vents on the side of the motor. Wrap the rubber sheet from the old motor onto the new motor and install the motor into the actuator housing. Make sure the wires are routed so that they are not pinched. Screw the access cover onto the actuator housing again and you are done. Well not exactly done. You still need to install the actuator in the car door, but you are very close. I suggest you plug the actuator into its harness to test before bolting it in place.

Contributed by Corbin

Cars Maintenance Interior_Maintenance Power Door Locks

Document statistics: Last modified on 2012-02-22 21:58:35 by Corbin

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