...and thought I'd share some of what I learned.

Let me start out with one tip: don't buy from the X10 web site. ANY site that poorly designed (I'm talkin' user interface NIGHTMARE here) doesn't deserve your business. A great place to buy (with MUCH better pricing) is Digitronix and their eBay store. You may want to use the X10 web site for product reference.

First, some background on how things work...

X10 makes several different modules -- wall switches, wall outlets, and dimable/non-dimable wall modules -- that control lighting and/or appliances in your house. The communication between these devices takes place through the actual wiring in your house. In order to communicate with the HomeLink buttons in your car, you need to introduce a wireless tranceiver into the pictue. This is a simple, little box that you plug into a wall outlet that has an antena coming out of it and a socket into which you can plug a lamp. Compatible wireless remote controls (including the HomeLink buttons in your car) can control the device plugged into this wireless tranceiver and any other X10 controlled devices in your house -- the tranceiver passes along the signals to the hard-wire connected devices.

Now that you've got the theory on how things work, let's turn to what I did in my house...

I purchased the following items:
- 3 wall switches ($20)
- 1 wireless transceiver ($9)
- 1 mini home keypad ($3)
- 1 credit card keypad ($5 - for the Montero)

Total with shipping came to $53.31.

Not having a garage, I have all three buttons at my disposal. So... what do with them?

I first installed the wall switches in the three places I had in mind for them (outdoor front, outdoor back, and living room), replacing the existing switches. Easy work here and each switch still has the ability to turn on/off the light AT the switch so you don't loose any existing functionality. I did play it safe and turned off the power at the main pannel before doing this work.

Next, I plugged the wireless tranceiver into an outlet in my kitchen that is physically close to my driveway to optimize reception. I plugged a small table lamp I have there into the transceiver.

When you install the X10 devices (switches/wall modles/etc.), you have to set two rotating switches on each one: a "house code" and a "unit code". The wirless tranceiver actually has just the house code switch; it defaults to a unit code of 1. The house code should be the same for ALL devices that you set up. The unit code should normally (more on this later) be unique to each device.

After I had all this set up, I tried things out with my wirless keypads. Yay! Everything worked just fine. Lights go on/off/dim using either the mini keypad or the creditcard pad from anywhere in the house. I did make one mistake and incorrectly set the unit code on one of the switches to be the duplicate of another so that they would go on/off together. I corrected it by removing the wall plate and adjusting the unit code (not knowing I would later take advantage of this happy mistake).

Now to program the HomeLink buttons in the car...

I took one of the X10 wirless remotes with me to the car (necessary to program the HomeLink buttons). The first step in reprogramming the visor buttons is to erase any settings that may already be in there. This is done by pressing buttons 1 and 3 simultaneously for about 20 seconds until the indicator light flashes quickly. Now, you can start programming the buttons. To do this, use two hands to simultaneously press the HomeLink button AND the X10 wireless button you want to map to it. Hold the X10 wireless remote within two inches of the HomeLink buttons on the visor and wait until the indicator light flashes quickly. It will start out by flashing slowly but you should not release the buttons until it flashes quickly. Repeat this procedure for each button you want to program. FYI, these instructions are also contained within your manual.

This is where I had to get a little creative...

The X10 wireless remote does NOT work like a garage door opener which opens/closes using the same toggle button; instead, it has independent buttons for on and off. As such, you cannot turn a given light on AND off with a single button. In order to do this, you have to dedicate TWO of the visor buttons; one for on and the other for off. If the only thing you care about doing is turning lights on, this is not a problem -- just map the X10 "on" buttons to the HomeLink buttons.

In my case, however, I wanted the option of being able to turn outdoor lights off while I was driving away. Here's where I took advantage of the "mistake" I made earlier. I changed the unit codes for my front and rear outdoor lights so that they are the same. Now, they both go on or off simultaneously when I use the remote control, but can still be controlled individually using the wall switch. In this manner, I was able to set one HomeLink visor button to turn on all my outdoor lights and another to turn them off. I set the third button to turn on the indoor lights to make life easy if I'm walking in with groceries/luggage. Again I did some redundant mapping by setting the X10 unit code for my living room wall switch to be 1 -- the same number as the table lamp in my kitchen.

Using some variation of the above and a little inexpensive hardware, you can take advantage of those unused HomeLink buttons to smooth transition between your Audi and your home.

MODS/UPGRADES:
17x8" BBS RKs (great AW story about how I got them...) | H-sport anti-sway bars | ToyGuy short shifter |
IceLink/iPod integration | Escort 8500 hardwire | fog/running light rewire | HomeLink home lighting control |
fold-down bag hooks in the trunk | aux power socket under the armrest | hidden Symphony EQ settings |
remote locking control recode | debadged

SUGGESTED READING FOR C5 A6 OWNERS:
2001 A6 info from AudiWorld | 2001 A6 info from Edmunds.com |
Audi 2001 maintenance schedule | Stoney's links (the ultimate A6 links page) |
the nOOb's guide to everything | how to make your car shine

The other ride: 1998 Mitsubishi Montero (typically with a kayak on top)