HomeLink is an aftermarket transmitter manufactured by Johnson Controls. HomeLink systems have appeared as factory equipment on many vehicles including Lincolns, Mercedes-Benz, Audi and others.
According to the Johnson Controls HomeLink website HomeLink can be programmed to control three items including your garage door, lights, alarm system etc. Obviously the receivers in your home need to be in place for the HomeLink system to work. I use HomeLink to control my garage door and it works brilliantly.
Audi started offering HomeLink on the A4 starting with the 99.5 series cars as part of the convenience package, although I believe it was available earlier on the A6 and or A8. The HomeLink is completely integrated into the driver's side sunvisor and as such it is a relatively straightforward procedure to retrofit the system into earlier cars. However, the lights for the vanity mirror have been moved from the visor to the roof on 99.5 cars. Fortunately for me, I open my garage door far more frequently than I use the mirror, but if this is a consideration you might need to consider an alternative.
What you will need
I ordered the HomeLink visor (part number 8D0-857-551-L-7SM) from Barry at Clair Parts Express ( baz@clair.com ). The unit cost $360.02 plus $5.25 freight. You will also need to provide Clair (or your dealer) with the color codes for your car (telling them that you have a 98.5 Brilliant Black car with Onyx interior will not suffice!). You will find the color codes in the manual or in the trunk. By way of example my color code is LY9B/LY9B NOC/BR. Barry was very good at keeping me informed and told me the item was on backorder for about five weeks. He also told me that Audi asked for the VIN number of the car. I don't know why they need this, although I can only assume that they made a note of it in their computer somewhere!
For the install you will also need a soldering iron, a small flathead screwdriver, and a regular sized phillips screwdriver.
Removing existing visor
While sitting in the car, unhook the existing visor and swing it out of the way to the side. The visor's left hinge/support is screwed into place in the headliner. The screw is covered with a small plastic disk with a slot in one side to help removal. Using the small flathead screwdriver, insert it into the slot that on the plastic disc that covers the screw. Be sure to insert the screwdriver deeply, because it is easy for it to slip out and gouge the plastic. With a little pressure, the cover will flip off and probably fly somewhere onto your dashboard (this didn't happen to me, but you may want to cover the dashtop vents so it doesn't fall down and cause a rattle).
Using the phillips screwdriver, unscrew the visor. The screw is very short, so again take care you don't lose it! Once unscrewed, flip the visor back so it is parallel to the windshield and pull down on the forward (windshield) edge. The bracket is hooked, so you will need to pull it out and forward to remove it. If your car is a 98.5 (I haven't checked other years), you will have pull down some wires with a connector. Unclip the connector, which is very easy and remove the visor.
Modifying the wiring harness
If you place the two visors side by side, there are a number of small differences between the two model years. The older visor has a flip cover over the mirror, which is centered and bracketed by two lights.
The HomeLink visor has a sliding cover over the mirror, which is slightly offset to the left. There are no longer any lights in the visor since they have been moved to the roof.
The older visor has two wires, one red and one brown, attached to a connector, which provide electricity to the lights. The HomeLink visor has those two wires, although they are red and black, which I assume links the on/off switch of the sliding cover to the lights in the headliner. However, the connector is a different shape and will not plug into the car! The HomeLink visor also has two more wires, one brown and one black, attached to a smaller tan colored connector. This tan colored connector carries the power to the HomeLink and obviously, the smaller connector also will not plug into the car.
In order to plug my visor in, I chose to remove the connector from the old visor and use it to replace the tan (HomeLink) connector. To do this, I cut the connector off the old visor leaving about half an inch of wire in place. I then stripped the ends of the red and black wires on the connector. I cut the tan connector off the HomeLink visor and stripped the wires on the visor side.
I then attached the brown visor wire to the red connector wire (the HomeLink will not work if you reverse these wires, so you might want to check it first) and soldered it into place. Solder the other wire, and presto, now you can plug the HomeLink straight into your car.
Installing the HomeLink visor
Installing the HomeLink visor is just like removing the old visor in reverse. Plug the connector to the car and cover with the anti-static foam. Push the wires back up into the headliner and hook the bracket into the slot. Screw the bracket in place and replace the small plastic disc to cover the screw.
Programming the HomeLink visor
When you receive the HomeLink visor there will be no instructions telling you how to program it! Fortunately HomeLink provides instructions on the website. Hold the two outboard buttons for about 20 seconds. Twenty seconds is a long time when you're sitting in your car, but wait for the LED to flash. Then, hold your garage door opener about one to three inches away from the HomeLink and simultaneously press the button on the opener and button you select to open your garage on the HomeLink. Wait until the light flashes then release the button. Obviously, if you are doing this in your garage take care to ensure that there is nothing blocking the garage door that could be hurt or damaged while you are programming.
