Tech Article Title Author Date
Adjusting A6 Brake Light Sensitivity Doug Gallagher 2001

Here's the procedure for adjusting your brake light sensitivity. How do you know if you need to do this? A good indicator is to see how far the brake pedal needs to be depressed to disengage the cruise control. If your pedal has ANY significant travel required to accomplish this (like more than 1/4") this is probably for you. (Or you can have it adjusted at the dealer if you don't consider yourself that handy.) While this procedure worked well for me and I have done my best to accurately document it, in no way do I assume any liability or responsibility in any way for any adverse or other ill effects which may result from it.

Anyone with basic mechanical ability can do this. Actually, the hardest part is getting under the dash to make the adjustment. It should only take 15-20 minutes (30 mintes tops) and requires the following tools:

a) flathead screwdriver
b) hex wratchet
c) pliers (not needlenose)

Naturally, you'll want to have the car turned off while doing this. These instructions were developed/performed on a Tip car, I'm sure some differences exist for the M6 cars.

1) Using the hex wratchet, remove the two hex bolts at the bottom of the dash panel on either side.

2) Remove the fuse panel located on the side of the dash. Locate the hex bolt seen through the hole to the right and remove it. (Don't worry if it drops, it will fall out when the panel is removed.)

3) Remove the trim panel across the top of the steering column by GENTLY pulling it towards you and slightly upwards. Remove the two hex screws this was hiding! (Tricky, eh?)

4) You can now let down (but not remove) the dash panel. Remove the computer connector from the panel by depressing the plastic tabs and pulling it out. Disconnect the lighting wires, make a note of which connector was connected to which tab using wire color.

5) Now remove the lower dash panel and carefully set it aside.

6) Position yourself under the dash, looking upwards at the brake pedal lever arm. You will see a clear plastic plunger switch mounted through a hole and touching (hopefully) the brake pedal arm. The other end of this connector has a 4-wire electrical connector attached to it. This switch has two sequential contacts used for the following:

1st contact - Indicates to on-board computer that brake pedal pressure is being applied. Allows shifting from "P" on tip models and disengages cruise control if in use.

2nd contact - Activates brake lights.

As the brake pedal is depressed the first contact closes and then the second very shortly thereafter.

The switch is mounted in a spring-loaded metal "grommet" through which it is threaded to control distance from the pedal. In order to make the adjustment, you must turn the switch within the grommet (not within the mounting hole!) so this requires you disconnect the connector with the electrical wires. You MUST hook this back up correctly so use identifying features on the connector and switch to note the proper alignment of these. (In my case the connector had a dark pink area which I lined up opposite the audi ring embossing on the opposite side of the switch.)

7) Remove the electrical connector from the switch by gently lifting the plastic tabs on each side using the flathead screwdriver. Remember to note the position of the connector relative to the switch.

8) While holding the metal grommet in place with the pliers, turn the plastic connector to acheive the desired effect. It's a standard right-hand thread so when viewed looking towards the firewall and turned by grasping the electrical connector end:

Clockwise - INCREASES the pedal travel required to throw contacts, brake lights engage later.

Counter-clockwise - DECREASES the pedal travel required to throw contacts, brake lights engage sooner.

I imagine most will be making the counter-clockwise adjustment at first. Don't worry if the best position is some weird increment like 1/3 or 1/4 turn, after you adjust the switch in the grommet simply rotate the entire assembly to get the correct alignment with the electrical connector and still keep the distance you've set the same.

9) After making your initial adjustment, replace the electrical connector on the switch in the correct alignment and enable the ignition (no need to start) and view the transmission lockout lamp on the Tip shifter. If it's off and there's no pressure applied to the pedal, you've gone to far. Turn everything off, remove the wires from the switch and turn the switch clockwise until the light comes on when no pedal pressure is present. (For you M6 folks, not sure how you'll gauge this.) Repeat this procedure until the desired effect results. When the switch has been adjusted properly, there should be minimal (almost no) brake pedal travel required to switch off the transmission lockout lamp. If you've done this, the sensitivity is adjusted properly and you can rest assured your brake lights will come on as soon as possible when you've got pressure (even light) applied.

10) Double-check your adjusted setting. Make sure the brake lights aren't on when no pedal pressure is present. If the tip lockout lamp flickers or doesn't return to lit when pressure is removed, you're probably a little to close to the hairy edge. Best to give it a small clockwise (1/4 turn) adjustment to be safe. If your cruise control isn't working, this is another good indicator that you've over-compensated.

11) Position the lower dash panel underneath the dash being sure to slide the end at the firewall into the two plastic brackets that hold it in place. Re-attach the computer connector and light wires to the lower dash panel. Replace the panel using the hooked connector at the bolt hole just to the left of the steering column to hold it in place while you replace all 5 hex bolts. Finally, replace the trim panel over the steering wheel column and the fuse panel cover and you're done!