[DIY] Converting Manual-folding M3 Mirrors into Power-Folding -- No 56K doityourself

[terraphantm]

Converting Manual-folding M3 Mirrors into Power-Folding Mirrors

Requirements:
• Manual folding M3 Mirrors
• Donor mirrors with compatible motors (another set of M3 mirrors; E39 M5 mirrors, and M3/M5 replica mirrors (YMMV with those – I don’t know if all molds are the same)
• T15 and T20 bits
• Optional but recommended: Blue Loctite (ideally 243 as some parts are greased)
• About 1-2 hours depending on how much experience you have.

This DIY is useful for two groups of people: People who already have manual folding OEM M3 mirrors and don’t want to paint another pair just for folding, and for people who currently have folding replicas and want to convert to power-folding M3 mirrors for minimal cost.

In my case, I already had OEM 12-pin M3 mirrors and wanted to convert them to power folding. As such, any steps required for 6-pin or ribbon cars are not detailed here. You should be able to manage if you use this DIY in conjunction with another guide specific for your style mirror.

I used a pair of OEM E39 M5 mirrors as the donors, but the steps are nearly identical if the donor pair is a set of replicas. If the donor pair is a set of power-folding M3 mirrors, it's actually a bit simpler.

I also did not cover removing the door panels or mirrors from the car, as there are many guides online that cover that material. So this guide will begin assuming you already have the mirrors off the car and ready for transplant. Without further ado, here’s the DIY:



Part I: Getting to the bracket

1. Remove the glass from both mirrors (if present). The procedure will vary depending on the build date – in the case of my car, the glass simply pops off. However older M3s had some kind of locking mechanism. Examine your mirrors to determine the appropriate method

2. Remove the adjustment motor. There are 3 T15 screws around the perimeter. You may have to push the motor in various directions to reach all the screws. Remove the motor, unplug it, and set it aside.



3. Remove the 5 screws holding the adjustment motor’s mount to the mirror’s frame.



4. Now there’s only 1 screw holding the base to the dome; remove that screw and separate the two pieces. Set the dome aside.



5. On the underside of the base, there are two T20 screws holding the bracket onto the brace. Remove them.



6. After some wiggling, you should be able to separate the base and the bracket.

7. On the bottom of the bracket, there’s a metal brace held on with 4 screws. Remove these screws and remove the brace. The wiring should stay with that metal brace. Set it aside.

Now that we have the bracket alone, I recommend disassembling your donor mirror to the same point. If your donor mirror was an M3 mirror - you're basically done. Just reassemble with the donor bracket/wiring. If you were able to acquire the motors separately, skip to part 2. Otherwise, continue reading.



Part I-b: Donor bracket specifics

The steps vary on the M5 and Replica mirrors slightly, but it’s similar enough that I’m not going to detail the entire procedure. The main differences are that the bracket on the M5/replica mirror also serves as the adjustment motor's mount. Also, the bracket does not fit through the mirror housing's opening, so you have to slide it through the other way (thankfully the wiring easily separates from the base, unlike the M3 mirror). One part I will spend some time detailing is removing the motor's wires from the rest of the harness:

1. Look at the connector. Notice how on one side there seems to be some kind of tab. Take a screw driver, and stick it between the block of pins and this tab. You should be able to pry out the block. (Sorry I forgot to take a picture of this tab)

2. Now locate pin 1 and 2 – you should see a blue and white wire in them. Remove these wires (poke a small object onto the tab, and slide the wire out. Don’t force it if it feels stuck – just look for where it’s getting stuck and depress that point).



3. Separate these wires from the entire harness (should be a matter of cutting some electrical tape)

4. Separate the bracket from the rest of the assembly

Okay now you should have two brackets – one from the M3 mirror (top), and one from the donor (bottom).You’ll notice that the donor bracket has a blue and white wire sticking out of it. These power the motors. Now let’s swap the motors.







Part II: Swapping the motors

1. At the top of the cylindrical portion of the bracket, you will see 3 T15 screws. Remove these 3 screws on both brackets. After removing these three screws, you should be able to separate the motor and the bracket with a little bit of effort. (On the manual-folding bracket, there’s a “dummy” motor held on in the same manner)



2. Look at the motor – you will notice that there are 3 notches of different sizes. Now look inside the M3 bracket and you should see 3 matching extrusions. Line these up and slide the motor into the M3 bracket.



3. Attach the 3 screws. I recommend using blue Loctite here as these screws are known to come loose on occasion

Assembly is basically the reverse process, except we need to add the wires to our E46 harness. Here are the details for that (sorry I forgot to take pictures)

On the metal brace that holds the bracket to the mirror base, there's a rubber plug that keeps the exist harness organized. Pull this plug up, pull the blue and white wires through, then push the plug back down.

Bring the wires through the base. Now you'll notice a rubber boot that wasn't there on the M5 mirror. You'll need to snake the blue/white wires through these if you want to keep the factory seal. Basically just force the wire through while taking precautions to not break the connectors. The wires are longer than the rest of the harness. I just looped the slack and taped it up. If you want everything to look OEM, get that fabric electrical tape and go over the whole harness.

After the wire is through, you'll want to insert the pins into our connector. Separate the pins from the locking mechanism. Insert the blue wire in to pin 1, and white into pin 2.

The rest of the assembly should be exactly the opposite of the disassembly procedure. Once the mirrors are fully assembled, install them on your car, and enjoy your newly folding M3 mirrors! Coding may be required. Here's a video of mine in action.