Mercedes have an optional integrated garage door opener system available for most models. It is integrated in the rear view mirror and can be seen by the fact it has 3 buttons on the bottom of the mirror (most models except SLK and the W163 (last generation) ML. The integrated garage door opener is made by Homelink.

It is a relatively cheap factory fit option compared to the price of replacing the mirror with one with the integrated opener - mainly because you have to buy a whole new mirror and the mirrors with the dimming glass and with memory are expensive to start with.  UK RRP for a mirror with integrated remote control is about £700. Factory fit price is under £200.

The integrated garage door opener is made by HomeLink (part of Johnson Controls Inc) -  Homelink also put the same mechanisms into most cars - so this information applies to most cars.

Much of the information in this document is not in the Mercedes WIS database and thus it took a fair amount of digging to get the info. The same is true of the BMW as we had the same issues making the integrated Homelink garage door opener in a new BMW.

There are two types of system, the North American system, and the rest-of-the world system. The Mercedes option codes are 232 (North America) and 231 (Rest of the world).

This document only applis to the option code 231 system, although may have some relevance with the North American system.

General Notes:

Details of the compatability of the latest mirrors and operating instructions for different vehicles are available from  www.eurohomelink.com

The garage door opener has 3 buttons which can be assigned to 3 different remote controls. Button 1 is on the left when looking at the mirror glass

There have been various releases of the software, each release has more compatability with different gargae door openers. You can see the software release by holding down button 1 (for upto 100 seconds !) until the light stops flashing, it will then turn off for a couple of seconds and the flash - count the flashes, 5 flashes = Version 5.  My 2004 mirror has Version 5 - the current release is Version 7

The mirrors have region codes. When a new mirror is supplied it is always set to 'Europe' (code 1) - but that is no good for UK and other markets. If you hold down the button 2 using the same process as for finding the software release above, 1 flash = Europe, 2 flash = France, 3 flash = UK, 4 flash = Italy.  -  Mercedes and BMW seem to have no information about this in their service databases, but if set wronly many garage door openers (for instance those using 418MHz transmitters like many FAAC systems) will not work.

Homelink's customer service is excellent, you can phone or email them (contact details on website above), and they will supply you with compatability lists for older versions of the software.

Usage instructions

You can reset all learned remote controls by holding down buttons 1 and 3 until the lamp starts flashing after about 20 seconds. This should be done if you get a new mirror or used car with the mirror in.

To assign a remote control to the button, hold down the mirror button and wait until the lamp starts flashing (if its already assigned to a remote this will take about 20 seconds, else about 2) - the whilst keeping the button held press the garage door opener button until the lamp starts flashing fast.

If this doesnt work, check the region code of your system and check it is right for your country.

The procedure for synchronising with 'rolling code' gate systems is more complicated and can be found in the owner's manual for your car.

Changing the Region Code of the Homelink Integrated Garage Door Opener

The Mercedes (and BMW) dealers don't seem to know about this important information. All new mirrors supplied as a part are set to region code 1 (Europe) and in UK. France, Italy need to be changed

Hold down buttons 1 and 3, after about 20 seconds the lamp goes out, and then let go (this resets the mirror)
Press and hold buttons 1 and 3 again, and then after 1.5 to 2 seconds press the 2nd button briefly, it will flash to tell you the region code, press the 2nd button again to change to region 2 (and it will flash twice), again once for region 3 etc.  Region 1 is Europe, Region 2 is France, Region 3 is UK, Region 4 is Italy.

Other notes about retrofitting a mirror with the integrated garage door opener

There are various different options that can be part of the mirror - making it hard to get the right mirror

1. Left or Right hand drive - many mirrors wont turn toward the passenger side (especially those with memory) - so get the right one
2. Auto-dimming - auto-dimming automatically dims the mirror when light shines in at night - if buying a new/replacement mirror, even if your car does not have this option you should get a mirror with this facility. If you look at the mirror you can see a little circle in the top right of the mirror glass - that is the sensor - you can see this in the picture at the bottom of this article.
3. Option 231 or 232.  Get the right one, 232 for America, 231 everywhere else - the frequencies are different so the wrong one will not work
4. Memory - some cars have memory interior mirrors (for instance pre MY2005 SL does, but they dropped it after that) - if your car has seat memory you should get one with memory if you can - you can tell because there is resistance when you move the mirror by hand
5. Single Phone microphones or not. Cars with telephone prewiring have microphones in the mirror. The exception to this is the older SL/C/S (pre MY2005) where there is a single microphone that is part of the mirror base, but it just unclips so there is no need to worry whether your new mirror has that or not. Again the microphone (black circle in this case) can be seen in the mirror picture below,
6. Multiple microphones: Microphones on newer cars (those from about mid 2004 when DVD based COMAND systems where introduced, and all the W211 E/CLS class cars) are built into the bottom of the mirror - there are 2 or 4 depending on the car there.
7. Colour - watch the colour, there are 2 blacks for instance (black, and anthracite - so cars with anthracite alcantara roof linings get the anthracite coloured mirror.

There is no Right Hand Drive option 231 mirror for the W164 ML

There is no option 231 for the W163 ML (there is for North American W163 ML)

The mirrors clip into place with a very strong clip, and all the wiring plugs into the overhead control panel (the one with the interior lights), or the microphone connector nearby. Each model comes apart slighty differently, some you remove the OCP first (again, that clips in, and you use a wedge to unclip it),

Picture of mirror with auto-dimming, single microphone and integrated garage door opener (courtesy of www.benzworld.org ).