For removal and installation of the actuator on E30 models, the procedure is as follows, 1. Take off the door panel and the water shield. Pull the actuator off the linkage and remove the screws that are holding it and get the wiring off the actuator. While assembling lock the actuator and the linkage and then join it with the actuator and then install by means of screws loosely. Tighten the screws and remove any freeplay in the linkage by compressing the actuator drive; later test the locks and refit the door panel. E36 models can begin by taking off the door panel and the water shield. On the front doors simply remove the guide rail nut and fold the guide rail down and then detach the wiring and linkage from the actuator. For rear doors, as with the other cars, the window has to be stripped together with the access panel and the wiring and linkage have to be disconnected from the actuator. Third, take out the three bolts that hold the latch and the actuator to the door structure and lastly place them in the reverse order but before doing this apply some threadlocker on the bolts.