Passenger Door Lock actuator broken
 

My M3 convertible (E36) has a bad passenger door lock actuator. It won't lock when I arm the car, and won't unlock when I disarm the car. it won't toggle when I press the little lock button on the car's center console. I don't hear it trying to actuate the lock either. No sound coming from it. I'm looking for advice on where to start looking. I checked the fuses under the hood as a 1st step, and haven't looked or checked elsewhere yet. If it is the actuator (and I heard this is probably what it is), can I get the actuator out of the door w/o having to remove the window? I got myself the Bentley manual, but it doesn't talk about the door lock actuator AT ALL. Weird.

thanks in advance.

Anyone got any ideas on this one?

I figured this out and the steps to take. First off, you can check the voltages to the lock actuator w/o taking lock actuator out. Wedge something into the loop hole on the body where the door latches, so you can use the button to lock and unlock the doors even when it's open, and hook up a 5v lightbulb or multimeter to look for the voltage spikes between the heavy-gauge black wire and one of the other heavy wires when you press the lock button. (I used a digital multimeter with a single-run trigger so I could look at the waveform!). but another lock actuator, a functioning one, could be used too. Turns out it was the lock actuator. I eventually succeeded in taking the actuator out without removing the window first (it was near impossible, but still possible).. The actuator looked perfectly fine, but it just didn't work. The new one worked just fine! That's all I know.

Glad you figured this out. Thanks for posting the solution for others. :wave