Article by: Adam B. Hocherman
Article applies to: all e36 models.
Introduction
Fig. 1. Door lock actuator.
Terribly inadequate information about this procedure can be found in Bentley, p. 515-6.
For those of you out there that have not yet purchased the Bentley manual for your E36-series BMW, it is not necessary for this procedure.
Allow me to summarize what Bentley had to say:
Step 1: Remove door lock actuator.
Step 2: Install new door lock actuator.
Hence the motivation to create “The M Files” which you are happily reading right now. Although it took me a total of about three hours to complete this procedure (including door panel removal) I could do it again in about half that time. As such, my pain is your gain – allot about 2 hours for this procedure.
Note: This procedure assumes that you have already removed the front door panel.
Step 1: Peel Back Vapor Barrier
Being careful not to rip it, slowly peel the vapor barrier away from the door, exposing access to the door lock mechanism and actuator.
Fig. 2. Remove vapor barrier.
Step 2: Remove Inside Door Handle
Using a Phillips screwdriver, remove the screw holding the inside door handle (black plastic just barely visible in below photo) to the door. Once the door lock mechanism has been loosened the interior door handle slides towards the rear of the car for removal. The inside door handle can be completely removed to relieve stress on the connecting rod. The connecting rod also slides within a small, white plastic bracket – snap this out now.
Fig. 3. Inside door handle mounting screw.
Step 3: Remove the Door Lock Assembly
The door lock assembly and its related linkages is not the best bit of engineering I’ve observed in this car.
The door lock assembly is rigidly attached to the far end of the door with three T30 Torx screws.
Fig. 4. Door lock assembly mounting screws (T-30 Torx).
This unit provides all of the following:
Latch mechanism (exposed through the hole in the end of the door).
Key lock (attached with a small steel linkage).
Door lock stem (the thing you press, by the window).
Outside handle connection (the whole lock mechanism “hangs” on this linkage – more on this later).
Inside door handle connection (attached with a long steel linkage).
Door lock actuator mounting point (the holy grail for this procedure).
Remove the three mounting screws. The door lock mechanism will hang freely inside the door.
Step 4: Remove Door Lock Mechanism From Outside Door Handle “Hanger”
Okay, this is the hardest part. The door lock mechanism is hanging on a metal “hook” that creates the linkage between that mechanism and the outside door handle. This hook points “away” from the opening in which you are working and is visible in figure 6, below. What you need to do is to lift the entire door lock mechanism up-back-down off this hook. This is most easily done while holding the door lock mechanism at a significant angle (maybe 30 degrees). The best advice is to simple fiddle with it until you get it off. You can now maneuver the entire unit within the opening.
Step 5: Cut Wire Tie and Remove Wiring Harness
A small wire tie secures the wires that run to the door lock actuator to the door – carefully cut it off. Next, get your hands in the opening and while holding the door lock mechanism with one hand, pull the actuator wiring harness down and off of the actuator. The direction of motion should be obvious to you from looking at the pin-slot arrangement that is built into the harness clip.
Fig. 5. Door lock mechanism hanging freely. Wiring harness removed.
Step 6: Remove Old Door Lock Actuator
The old door lock actuator doesn’t simply “pop” off as some may have told you. The secret is revealed in the photo below (figure 6) which shows the door lock actuator mounting point sans the actuator. What is difficult to see in the dark is the black plastic “wall” or “clip” which is what actually holds the actuator in place. Using a flat head screwdriver, pry the old actuator off of the mount from both the bottom and the back, alternating as necessary. You need to bend that “wall” back far enough, while moving the actuator upwards so that the actuator clears the little nubbin that holds it in place. The groove or hole visible in figure 1, above, is where this nubbin ultimately resides.
Fig. 6. Actuator mounting point (lock “hanger” visible in background).
Step 7: Attach New Door Lock Actuator
The new door lock actuator can now be snapped in place. Two slots in the actuator line up with the two metal alignment points on the actuator mount. The sliding portion of the actuator sits over the curved connection point between these two pegs. Line these three points up and push the actuator down until it snaps in place. Reattach the wiring harness.
Step 8: Completing the Job
Great! You’re essentially done. Test the actuator by pulling the door lock stem up and down. You should hear the actuator reacting at this point. The motion should sound smooth and unrestrained.
The last challenging part of this procedure is to rehang the door lock mechanism on the outside door handle “hook”. In the opposite fashion from the way you removed it, rehang the entire door lock mechanism. Again, this is tough and needs to be done primarily by feel.
Replace the inside door handle and screw next.
Reposition the door lock mechanism and reinstall the three Torx screws you previously removed.
There is black cloth tape around many of the wires inside the door that serve to protect the wires from chaffing. If your car is old this tape may be dry or rotting. I cleaned up the wiring with some fresh electrical tape. Install a fresh zip tie to hold the wiring to the door and ensure that this contact point is well wrapped.
Reinstall the inside door handle (if you completely removed it). Also, ensure that the connecting rod between the door lock mechanism and the inside door handle is properly seated at both ends. When I performed this procedure, the door lock actuator side of this rod had come partially out of the eyelet on that side and although the inside door handle worked, the rod was interfering with the actuator mount.
Reposition the vapor guard. If the gluey substance used to hold this in place is no longer taking, put a couple of strips of electrical tape around the edge to hold it in place.
Finally replace the door panel by first lowering the entire panel down and over the door lock (the part that you press up and down with your hand). If you disconnected any of the wiring harnesses, ensure that you have reconnected these firmly. Next carefully align the clips on the panel with the holes in the door. Use your palm to “pop” the panel back in place – don’t be shy, a good rap is required. Be careful to ensure that the metal alignment points along the top of the panel are aligned as well.
Replace the mirror adjustment switch (if you removed it) and the black trim around the door handle.
Fig. 7. Door (completely re-assembled).
Close the door. Pull up on the outside door handle FIRST, to ensure that the lock mechanism has set itself in the proper position to be closed.
Test your handiwork with the key fob, the key itself and, finally, from inside the car with the door lock stem.
Congratulations! You’re done. End of procedure.