To remove the door card, simply get a 5mm Allen key, and remove the 8 Allen head screws around the perimeter of the door. I tend to remove the bottom three first, then two of the side bolts, then one of the top two (located next to the hinge). This ensures that as you take the last bolt out, you don't have the whole weight of the door card resting on it.
At this point you may wish to lay down a matt, cloth or old towel to rest the door card on once the last bolts have been taken out, this saves the underside of the door card being scratched by a garage floor or driveway. From here you should have enough room to access the wiring, connectors and door position contact. If you wish to completely remove the door card then just undo two wiring connectors.
Upon refitting it is prudent to use copper grease on all the of bolts in order to stop them seizing.