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      09-21-2014, 04:52 AM   #1

808MGuy's Avatar
Drives: 2009 E90 M3
Join Date: Jun 2008
Location: Oahu, Hawaii

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DIY: Repalce door lock actuator

I recently came across a problem where my driver's side door would not unlock with the key fob or with the button in the car. The only way it could unlock is by pulling the handle inside the car or by manually unlocking it with the key in the key cylinder. All other doors worked normally and locking functions all worked normally which led me to believe it was a bad actuator. Today I replaced the actuator with a replacement I got from Tischer

BMW Part number - 51217202143
Apparently there are different part numbers for pre 3/2009 builds and post 3/2009 builds. This number is the pre 3/2009 build.

From what I've heard, dealerships will charge you around $500 for this repair. The part from Tischer was about $100 and it took about 1.5 hrs to replace with a good 30 minutes of that just trying to wiggle the actuator out of the door once I had all the parts/wires disconnected. I used the DIY on the E90 forum which was pretty good but I did take a few shortcuts which made it a bit easier.

Here we go...

Tools needed:

Plastic pry tools to remove door trim and door panel
T20 torx screwdriver bit
T30 torx screwdriver bit
4mm T-handle hex or just a 4mm allen wrench
10mm deep socket or standard socket with short extension

Small hands help

One major difference from the E90 DIY is that I did not unhook the window and I kept the window in the fully up position.

1. Use your plastic pry tools to release the first clip on the front side of the door panel trim. Pull straight out to release the clip.

2. Once the first clip is out, you should just be able to pull the rest out by hand working your way from front to back of the door. Once you get to the back end, there is a hook on the trim. Pull sideways towards the back of the door to release the hook. If you continue to pull straight out from the door like the rest of the clips, you will break the hook.

3. Once the trim piece is off, you will see holes with 3 T20 torx screws holding the door panel in place. Remove those screws. Some screws may not come all the way out with the screwdriver but just keep turning until you feel no resistance. The door panel will eventually come out and the screws will fall out when you turn the panel over.

Here's a closeup of one of the holes with the T20 screw in it

4. Once all the screws are out, the door panel is only held in by plastic and metal clips around the edges of the panel. Start at the top front corner of the panel and work your way down the side, across the bottom and up the other side until only the top clips remain. The top clips can be released by pulling straight out. Take note of how they are engaged so you know how to reinstall and engage the clips.

5. Once all the clips are released, lift the panel up slightly to clear the lock rod. Just behind the door lever, you will see a white bracket at the end of the lock cable. Pull the white bracket away from the door panel to release the lock cable from the door handle.

Door lock cable released

6. Now you can rotate the panel such that it sits on its side (front side up). You will probably want to put a towel or cardboard on the ground so keep from damaging the panel.

From here, you can disconnect the speaker wiring by pulling the connector straight out. You can disconnect wiring to the light at the bottom of the panel by pulling the connector straight out. You'll also want to remove the entire light housing and put it aside. It will help with reinstalling the door panel. Finally, you can release the door lock and window harness. This harness is locked into its socket with a locking connector. There is a button on the bottom of the connector. Push the button and then rotate the lever on the harness. Rotating the lever will force the harness out of the socket. Once free, you can take your door panel and put it aside.

7. With the door panel out of the way, you can now disconnect the various items from the actuator motor assembly. Remove the other end of the door lock cable from the actuator motor housing by pulling down on the white portion and then pulling away from the actuator housing. Once this is out, you can pull the black part at the top of the cable up to release it from the lock hook. Put the cable aside for reuse.

Pull the lock rod out of the white socket by pulling straight out. It will take a bit of force but it will come out. Keep that aside for reuse. Finally, remove the wire harness from the actuator assembly. Squeeze the top and bottom of the connector and pull straight out.

8. Pull the moisture barrier away from the door starting from the back side. As you pull away, make sure not to tear the barrier and use a utility knife to cut the sealant. Cut it down the middle so that some sealant remains on the barrier and on the door. This will make it easier to reseal it. If you don't get a good seal, you will end up with a puddle of water at the bottom of the foot well when the next big rain hits.

Now remove the 10mm nut holding the bottom of the window regulator guide and loosen the top 10mm nut but do not remove it all the way.

9. Now you can remove the 3 T30 screws holding the actuator in place. These were pretty tight so I had to use an impact driver to remove it. There is 1 on the face of the door and 2 on the side. Also remove the rubber cap near the top of the side of the door to reveal a 4mm screw that holds the door lock cylinder in place.

10. Loosen the 4mm screw but do not completely remove it. You can turn it quite a bit before it comes completely out but what you should do is pull on the door lock cylinder from the outside and keep pulling as you loosen the screw. It will eventually pull out. It does take a bit of force to pull it out but it does pull straight out.

11. There a few things on the inside of the door connected to the actuator housing that I could not get pictures of. There is another locking cable that is secured at 2 places on the housing. Both are identifiable by white plastic ends similar to what was on the end of the door lock cable. Pull those straight out of the housing from the inside towards the front side of the door. There is also a wire harness that is secured to the housing. It is not an electrical connection. Just house keeping ties to keep wiring neat. Pull those out of the holes they are secured to with your hands. They pull straight out but the space is tight and you have to pull hard. Small hands are nice for this step.

At this point I stopped taking pictures because I thought I was in the clear but that was not so. The actuator housing is now loose but getting it out of the door proved to be a real PITA.

12. As you recall we loosened the window regulator guide. If you push in at the bottom and slightly rotate it towards the front of the car, you can get enough room to wiggle the actuator out but it is tight and will take a bit of swearing and blood from scraping your knuckles on the sharp edges of the door.

13. Once out, reassembly is the reverse of the removal. I was not able to get 1 of the housekeeping wire harness connections back into the new actuator housing because my hands are just too big but I don't think it will be an issue.

14. Couple of items to note on reassembly. When reinstalling the T30 screws to secure the actuator housing in place, do the 2 on the side first and then the 1 on the face of the door panel last. It will be nearly impossible to lineup the screw holes unless you do it this way.

When reinstalling the lock rod into the actuator socket, make sure you push it in all the way. Note that the notch in the socket should face the same direction as the lock rod so that the rod will recess into the notch. It may not be pointed in the correct direction (up) when you install the rod but you can rotate after you snap the rod in place.

Once all the connections are in place, bring the door panel back and lean it up against the door so you can reconnect the door lock and window control wire harness. You will want to roll the window down for reinstallation of the door panel. This will help you line up with top clips of the door panel.

When reinstalling the door panel, start by inserting the lock rod into the hole on the top of the panel. Then secure the 4 clips on the top of the panel. Once in, you can work your way around the panel to engage the rest of the clips. Don't forget to reconnect all the wiring behind the door (speaker, door lock cable and light). For the light, it's actually easier to just let the wire hang out of the hole and then install the light housing after the door panel is on.

You will need to close the door to test since the lock won't go into the lock position with the door open.

One final note:

I've taken the door panels on my car off many times and it is nearly impossible not to break one of the plastic clips in the process. It is a good idea to have some spares on hand. They are only $1-$2 each at the dealer and the part number is 51418224768.
09 E90 M3 - Interlagos Blue / Black Novillo / Sycamore Anthracite / Eibach / HRE

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      09-21-2014, 08:12 AM   #2
Second Lieutenant

Drives: 2011 E90 M3
Join Date: Nov 2011
Location: PNW

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Nice write up.
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      09-23-2014, 07:00 PM   #3

808MGuy's Avatar
Drives: 2009 E90 M3
Join Date: Jun 2008
Location: Oahu, Hawaii

Posts: 2,287
iTrader: (3)

About the same time my lock actuator went out, I noticed issues with my car maintaining the memory from my key fob. All my radio presets disappeared and my seat and mirror positions would get erased. It would happen randomly even after I set them again. Ever since I replaced the actuator, all of those issues stopped. I'm not sure how the actuator plays into that but it seems like it was causing some type of electrical issue that would cause the car to lose the memory settings.

Also, I did not upgrade the 15A fuse for the actuator to a 20A like the E90 DIY indicates. I know there is a TSB that also provides this recommendation but I don't feel comfortable doing it. Unless the wiring was oversized from the factory which is rarely the case, increasing the fuse size could be a fire hazard.
09 E90 M3 - Interlagos Blue / Black Novillo / Sycamore Anthracite / Eibach / HRE

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