This instructiable details how to repair a Mini cooper door lock actuator. I did this to my 2003 mini cooper s. I was sick of reading about the countless number of people who have been forced to replace this poorly designed component with a new one ($130) because BMW made them "non-serviceable". This unit IS SERVICEABLE - if you are clever enough ;)
I would also like to thank the guys over @ NAM (northamericanmotoring.com).
Step 1: Are you sure you have a broken unit?
Confirm that in fact you do have a bad door lock actuator. Check  fuses  other door locks functionality  wiring harness.
get your tools ready. I used torx, flat head screw drivers, pin, acetone, multimeter, DC-power supply.