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!