Audi TT quattro Roadster, Radar Detector Install
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UPDATED 09/13/03

- Details -

These mods were done on a Roadster, using a Passport 7500 detector. It should also work for any other detector, or help provide a source for switched +12V.

To do this job properly, you will need;
A T-25 Torx driver.
A 10mm nut driver, or socket wrench.
A Volt-Ohm meter, or a 12V ligthtbulb, with two wires on clip leads.
A soldering iron, and accesories.
Electrical Tape.
A small flat bladed screwdriver, or a pick tool.
Bandaids.
A massage later.

You will need to remove;

The lower dash panel.
The fuse box panel, and fuse box.
The 'Concert' Radio.
The kick panel to the right of the gas pedal
The left or right vent grille on the dash.


Start be removing the 2 T-25 Torx screws from the bottom of the valence panel, under the steering wheel. Then open the fuse panel door, and remove *all* the torx screws as shown.


Pull the panel up a bit, and forward. You may have to reach down underneath, while inverted, to release this panel from 2 white nylon holding clips. The panel should easily drop down. It's a bit heavy, so be careful here. Leave everything attached to this panel. It should look something like this. Panicked yet?


Look underneath the console here, and to the left. You should see an area like this.

Look at the 4 terminal lugs. I show them here for reference. You can use these to see where you can tap in for the +12 V, but you need to be very careful if you do. These lugs are buss terminal feeds from the battery, to the fuse box. The RED terminals are LIVE +12V. If you tap into one of these posts, be sure you use an in-line fuse to your radar detector. The yellow lug at the left is "switched" by the ignition key/switch. Keep the lead as short as possible from the fuse holder to these lugs. In fact, I DO NOT recommend that you tap in here, if you are at all concerned about doing this. If you do not fuse a circuit coming from this area, you run the risk of melting a wire, and starting a fire. These terminals are 20 and 30 amps. or more. Any wire coming from these posts, and reaching ground, will immediately heat up, and become red hot like the coil heater in an electric oven. This will happen way before a fuseable strip will blow, if at all. Also, look closely at this pic, on the left. I added in the fuse, (transparent holder) on the left into a fused circuit to run my radar detector.


I removed all these screws from the fuse box area.

This will allow you to get at the back of the fuse box.


Once you free the fuse box from the panel, turn the whole piece so that the fuses are down, and you will see the back of the box. There are two plastic tabs that hook into the box that will free the back. Pull the back off, and it will look like this.


If you look closely at this panel, you will see that the fuse box is divided into sections. The middle section here that I have tried to outline, is switched 12V with the ignition switch. All the fuses here are switched by the ignition. My choice is to solder right to this copper buss bar here at this point. You can also tap into one of the wires here, by simply scraping off the insulation at one of these fuses, solder the connection, then tape it.


Look at this pic here. You should be able to see this same area in your car. The actual lug here is a chrome acorn nut, with a bunch of brown wires coming from it. This is the best ground spot to use. (All German car mfg. use brown as their ground wires.) You will need a 10 mm socket here to remove this. It's tightened very well. You will need two hands here to loosten this, one to hold the plastic piece, the other to loosen the nut, otherwise you risk snapping off the bolt and nut from the plastic holder.


Look at the panel, right near/behind the knee bolster. You will see this plug button. Carefully remove this plug, and the T-25 Torx screw. There is another one up a bit, under the dash. This will greatly facillitate you threading any cable up into the radio/heater control area.


Next, you will need to remove the radio, if you wish to get the cable for the detector into the top of the dash area.

You can stop here, and route the cable out into the center console, under the radio, by simply threading it through the center-split piece of plastic, under the ash tray. Take a close look at this. It splits open easily.


You can go to the dealer and find the Audi radio removal tool, or have the dealer remove your radio. (It will still work, if it is simply released from the DIN hole bracket).

You can fabricate a tool like this from a piece of sheet metal.
The tip is critical, as it needs to be this angle, and this length to release the clip. I have heard a small saber-saw blade will work here also, but don't mung up the slots on the radio.
Here is a shot of the radio removed, and upside down. The tool goes in then with the beveled edge to the inside of the radio.


You will be compressing this spring.


Here the tool has compressed the spring


You can then work the radio loose from the first side you have compresssed the spring. You can stick you fingers in the cassette slot, to pull the radio out at an angle, away from the first compressed spring. Remove the tool, and compress the other spring, pull the radio away from that edge, and you should be able to pull the radio straight out.

I do not have pics of this yet, but the radio is on a very short cable. Get a towel, or something like that, to put on the center console area, to rest the radio on, so you do not scratch either the console or the radio.


The Passport Remote Mute Switch


The Passport 7500 and 8500 come with a remote mute switch. This small plastic box with a push buton switch and LED's also have the telephone-type cable coming from it, and the power cable also, that goes back to the fuse box. I used black velcro to mount the switch here.


Top Vent Removal


Look at these vent pics. You can use a small flat-bladed screwdriver to remove the top vents, but be careful! This plastic is very thin here, and a number of people have reported they have broke off these tabs, or the vent pieces when removing this piece.

I use my small pick tool to get at these tabs.

This is a pic from the Audi service manual

This pic shows in the circle, the release tab area, that you need to move, to get it off the button-tab on the dash. This piece is wafer-thin! Note that it doesn't look at all like the service manual pic. Also, I had to enlarge the slot on the right here, to allow the cable to get through.


I do not have pics of routing this cable, but once you get the radio out, remove the kick-panel on the left under the center console by the gas pedal, and you have removed the lower dash, it's fairly easy to see how to route the cable from the detector mute switch, up through the top of the dash.

Check your work, turn on the ignition, and you should have power to your detector.

Reverse the removal proceedure for the panels, lower dash, etc., and you are done.

If you had to crawl on your back, to get under the dash, and your hand is scratched up from sticking it into small holes that have plastic and metal pieces find you that you can't see, then you understand why you need the bandaids and the massage.

Good Luck.

photo by jeff bipes
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By Jeff Bipes