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
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.Originally Posted by Part 1
Part I-b: Donor bracket specifics
Originally Posted by Part I-b
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
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)Originally Posted by Part II
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.