DIY: HomeLink + auto dimming rear view mirror retrofit.

[themadrussian]

I tackled the auto dimming mirror w/HomeLink (garage door opener, called UGDO by BMW) retrofit today. I didn't plan to make this a DIY, so sorry for the lack of pictures. I did this on my 04/99 E36 M3 coupe with a sunroof. The wire colors may be different in your car.

You should be able to do this on a car without a sunroof, but I'm not sure how to access the map light wiring harness (required) on a car like that, so you're on your own. I don't have an alarm, so I did not bother looking for the wiring harness with the provision for the alarm LED wire(s).

So I bought an E90 rear view mirror with homelink and auto dimming off eBay for ~$140. I then purchased the appropriate set of end caps, the retrofit wiring harness (from the E53/E39 ETK), and the grommet for the wiring for ~$40.

The part number for the mirror I bought is 51167028444. The part number for the retrofit kit is 51160001231. It's ~$25, and includes the wiring harness, 3 BMW wire taps (I found these useless), and a grommet. The part number for the end caps is 51167133655. It's ~$10 for the pair of covers.

Mirror:



HomeLink buttons:



Wiring harness, grommet, and the BMW wire taps that I didn't use:



End caps:



First, remove your existing rear view mirror. Tilt the mirror downwards, and grab the base, where it connects to the windshield. Gently turn it counter-clockwise, until you get to approximately 45 degrees. The entire mirror should now pop off the windshield, easily.

The next step is to remove the sunroof motor cover / panel. It just pries out (gently) from the top with a flat-head screwdriver. Disconnect the sunroof up/down switch.

The next step is to remove the map light assembly. You'll see some black clips at the top of it. Push those, and push the map light assembly down and out. It will fall. Let it dangle.

Then, insert the wires through the provided grommet (small end of the grommet is pointing towards the bare end of the wiring harness), and run the grommet all the way to the mirror connector. Plug the cable into the mirror. Put the end caps in position, put the grommet at the top (making sure it is all snug), and clip on the end caps. This might take a few minutes of fidgeting, but you'll get it eventually.

Now, take the bare wires from the harness, and while pushing down against the trim behind where the map light assembly normally sits, you should be able to feed the wires over it and into the map light assembly/sunroof motor area. Pull the harness all the way through.

Make sure the grommet and end caps are snug, and then, with the base of the mirror at a 45 degree angle to the windshield, push it onto the base cap on the windshield (it should pop on) and then rotate it 45 degrees clockwise to lock it position. It should look OEM at this point.

Now, back to the map light assembly. It is connected with a wiring harness, which you will need to find and remove. It's clipped on, to the left of the sunroof. Take it off, pull it towards you, and disconnect the map light assembly from the connector.

The map light assembly connector (it's the white connector on the left in this picture):



At this point, you need to locate two crucial wires. One is violet with a white stripe, and one is just plain brown (there is another with a stripe, this is not the correct wire). The VIO/WHT wire is hot with igntion in ON. The BRN wire is for ground. Going from left to right, you should have a Violet/White wire, a Red/White wire, a Red/Black wire, a Brown wire, and a Brown/Red wire. The 1st and the 4th wires are the ones you are going to need to cut and/or splice into.

You may want to cut off most of the wiring harness at this point (you only need 6-12 inches of slack at most), and peel/cut back the BMW black tape. Splice the brown wire from the dangling mirror harness into the brown wire on this harness. Splice the green/white wire (homelink/autodim power) from the mirror harness into the violet/white wire. If you want to hook up the autodim-cancel when the car is in reverse, run the blue/yellow wire down the a-pillar to a reverse light indicator source. I didn't bother with this, because I'm lazy.

Reconnect the map light assembly to the harness, tuck it back into position, and reinstall the map light assembly. Plug the harness for the sunroof open/close switch back in, and insert the sunroof trim panel back on. It's not easy (I had to do some major bending/fidgeting to get it back on).

The HomeLink and autodim should now be operational. They should only function with the ignition in ON. To program the HomeLink, first, hold down the 1 and 3 button until the orange LED flashes quickly and constantly. Let go of the buttons. Get your garage door opener, and hold down the button on the mirror that you want to program. The LED should turn on and stay on (or it might turn off, I'm not sure). Either way, keep holding down the button. Then, press and hold your garage door opener button. After 3-4 seconds, the LED should begin to flash quickly. Let go of all the buttons. Your HomeLink should open/close the door, now. Rinse and repeat for the other side.

Finished product:

[Eddie916]

Thanks! I asked for this DIY last night I think.
Doesn't this retrofit work also with a cheaper Land Rover mirror that's actually identical?

[RRSperry]

Yes the Rover mirror is the same.

I really want to get around to wiring the reverse light to the mirror. It's a pain backing up in parking lots at night, what with tinted windows, and a dimmed mirror...

[themadrussian]

Yes the Rover mirror is the same.

I really want to get around to wiring the reverse light to the mirror. It's a pain backing up in parking lots at night, what with tinted windows, and a dimmed mirror...

It shouldn't dim the mirror at night unless there's glare / bright light coming in through the rear window.

[JetBlackE46]

This great - thanks!

One question though...since the mirror is always powered, if I parked in my driveway or something can someone still "open" my garage door if they break into the car? I'm assuming that if I found a switched power source that the opener would only work when the key is in the ignition?

[tonio]

Looking good! Are there wires showing from the mirror going to the headliner?

[ndcruz]

This is perfect. I bought a Rear View Mirror from a Range Rover a while back, I just never got around to installing it.

Does the LED on the mirror light up? or the Red Alarm light?

[themadrussian]

This great - thanks!

One question though...since the mirror is always powered, if I parked in my driveway or something can someone still "open" my garage door if they break into the car? I'm assuming that if I found a switched power source that the opener would only work when the key is in the ignition?

The mirror is not always powered - it requires the ignition to be on in order for the homelink or the autodim to function.

Looking good! Are there wires showing from the mirror going to the headliner?

No - that's what the grommet is for - it covers up the wires and is nice and snug between the top of the base and the headliner.

This is perfect. I bought a Rear View Mirror from a Range Rover a while back, I just never got around to installing it.

Does the LED on the mirror light up? or the Red Alarm light?

My wiring harness did not have a wire for the alarm LED. It doesn't light up. Think of it like a false deterrent.

[Braymond141]

Maybe I should make a harness kit that would be a switchable powered source and include the tap for the LED...

[RRSperry]

If the mirror has the clowns nose there are more wires. It's a 10 pin connector. You can wire the nose to your existing alarm led leads.

I powered the mirror from the switched power going to the sunroof motor. I didn't want it working when the car is off.

Bright lights in parking lots, and at my house, (dark garage, and bright floods) cause the mirror to dim. Hence the desire to make the reverse light connection.

[libravcs]

Nice work.

FYI..for anyone wanting a cheaper alternative for basic (and invisible/stealthy) garage door opening and one that wont work unless the key is available...

http://www.smarthome.com/7458F.html

[Dricebrug]

Yep. I'm doing that.

[BadBoostedBmwM3]

I can't wait to do this!!! I love my homelink or "UGDO" in my e46...
BUT, in my e46 and my dad's the UGDO is NOT always "hot"; it turns off when the car turns off. SO, if someone broke in then they can't open the garage...

[themadrussian]

If the mirror has the clowns nose there are more wires. It's a 10 pin connector. You can wire the nose to your existing alarm led leads.

I powered the mirror from the switched power going to the sunroof motor. I didn't want it working when the car is off.

Bright lights in parking lots, and at my house, (dark garage, and bright floods) cause the mirror to dim. Hence the desire to make the reverse light connection.

The mirror doesn't dictate what wires the harness has. The mirror has a 10-pin connector, yes - that's the standard size. The harness I bought was the only retrofit harness I was able to find at the time, and it only has three wires. It has one wire for ground, one for HomeLink/Autodim power, and one to cancel the autodim in reverse. You might have some luck with this PN for the wiring harness for cars with alarm: 61120140175. Use that at your own risk, though. It's moot for me, though, since I don't have an alarm.

I can't wait to do this!!! I love my homelink or "UGDO" in my e46...
BUT, in my e46 and my dad's the UGDO is NOT always "hot"; it turns off when the car turns off. SO, if someone broke in then that can't open the garage...

The Homelink buttons in my sister's '04 Toyota Sienna, my dad's '04 Acura RL, and my mom's '05 Acura MDX are all hot at all times.

[BadBoostedBmwM3]

The Homelink buttons in my sister's '04 Toyota Sienna, my dad's '04 Acura RL, and my mom's '05 Acura MDX are all hot at all times.

Thats odd... I guess BMW actually thought of the worst case scenario.
Either way I love the retrofit... and Im doing it. Props to you!

[fast1eddy]

How do you like the auto dimming feature? My wife has it on her E46 and hates it. I'm not a big fan either. Makes it harder to judge the distance of cars behind you imo.

[themadrussian]

Indeed, the green wire is for both homelink and autodimming power. The blue wire is to cancel the autodim when the car is in reverse.

You should hook up the green wire to the violet/white switched power, and then homelink will sadly only work with the ignition on. The first post is updated to properly reflect this.

How do you like the auto dimming feature? My wife has it on her E46 and hates it. I'm not a big fan either. Makes it harder to judge the distance of cars behind you imo.

I mean, it does the same thing that the manual dipping feature does, except it does it automatically. My dad's old Infiniti (which I used to drive a lot) had it, and it was a very nice feature, IMO.

It doesn't bother me one bit - on occasion it won't dim as much as I'd like, but it's quite nice to have an undimmed rear view mirror at night when there aren't any cars behind - with a manual dipping mirror you'd have to keep dipping it up and down, which is annoying, and people don't do it.

[RRSperry]

Just like the Euro drivers side mirror. You get used to it. Now my Audi and the BMW have autodim. But the Audi also dims the outside mirrors.

[themadrussian]

Just like the Euro drivers side mirror. You get used to it. Now my Audi and the BMW have autodim. But the Audi also dims the outside mirrors.

I believe some newer BMWs also have auto dimming on the side view mirrors. I've seen the retrofit kits in the E53 (X5) ETK. The mirrors are like $625 MSRP per side.

I think the E9X has autodimming side mirrors.

[M3C]

Is there a space to install BMW Homelink on the E36 sunroof motor cover without doing any modifications?

[EURO M3 CSL]

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[toplessinokc]

What a cool idea. Great write up.

[jasonf860]

Anyone know where to find the signal for the reverse lights so you can hook up the auto dim cancel?

[themadrussian]

Is there a space to install BMW Homelink on the E36 sunroof motor cover without doing any modifications?

Not unless you remove your sunroof motor.

Anyone know where to find the signal for the reverse lights so you can hook up the auto dim cancel?

I'm guessing you have to run it down the a-pillar and find it somewhere under the dash. A Bentley manual will help you out here. You can run the whole harness down there, since they give you PLENTY of wire length.

[jasonf860]

Thanks. I'll have to consult the Bentley's wiring diagrams. i bought mine off eBay for $40 shipped. Off a 99 528i, came with the wiring cut from the car also.

FYI: for the clown nose: Pin #8 is positive, pin #9 is negative.