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Installing factory digital compass mirror in Audi A4 B8 and A5 (by SplendidAudi)

24.2.2009 (updated 24.2.2009) - SplendidAudi sent in this contribution. Thank you! Published and edited with permission. SplendidAudi also posted it here:

Installing factory digital compass mirror in Audi A4 B8 and A5

I have now installed this in two early model year 2009 cars using two methods below. Both cars had side assist, dimming mirrors and three zone climate control from factory.

These instructions are probably not valid for cars with lane departure warning! Also starting from 11/2008 some changes are listed for mirrors by Audi, not sure if those cars are different. My install cars were older than that. Check schematics and with your dealer if necessary.

Digital compass mirror is different depending on if your car has one or three zone climate control, because mirror includes a climate sensor behind it in three zone cars and not in one zone cars.

Cars with one zone climate control use compass mirror part 4F0 857 511 F with six pin connector. This part has no holes in the base part plastic behind the mirror. You can also mod this to a car with three zone climate, instructions below. This part is also for A6 and others I think.

Cars with three zone climate control use compass mirror part 8T0 857 511 B with eight pin connector. The base part plastic behind mirror has holes in it that show climate sensor through them. The mirror should come with the climate sensor (part 8K0 907 658) in there, but if not see late in this article for instructions how to move it from old mirror to the new mirror.

Note that part number adds letters to end depend on car interior colour. 8T0 857 511 B Z62 for example is mirror for default light interior. Order the correct part carefully.

Method 1:

When installing correct part for one or three zone climate control cars, installing the mirror is easy. This is same for one and three zone climate control cars, just the mirror part is different. Order correct part for your car, see above.

This method is same for A6/Q7 cars too I think.

When you get the correct mirror:

Disable battery power for safety.

First remove the vertical cable cover above mirror by pulling it out downwards. Wiggle it maybe.

Remove connector.

Turn old mirror counter clockwise until it frees.

Put in new mirror, turn clockwise until it snaps.

Connect new connector to car. Snap in place.

Replace cable cover.

Reconnect car battery.

Switch on ignition. Mirror shows C. If not, see car manual how to activate compass. Basically control it by holding down mirror button enough times.

Read car manual for how to set compass zone and calibrate by driving a circle. Done!

Method 2:

When installing one zone climate control mirror part 4F0 857 511 F to car with three zone climate control. (For example if you source a used part.)

See method 1 for how to remove the mirror from car. Then go to a table to continue work on mirrors.

Your old mirror has 8 pin connector and new mirror incorrect 6 pin connector.

Remove 6 pin connector plastic from new mirror cables. You will not need it. The connector has small plastic lock you must lift open before removing it.

Write down pin numbers and wire colours from old mirror 8 pin connector. Remove 8 pin connector plastic from old mirror. Store safely.

Remove base part plastic and climate sensor from your old mirror. You need this later. To do it, pull left and right the base part plastic from top and push down. It will release. Remove climate sensor connector and base part plastic with sensor is now free. Store safely.

Remove base part plastic from new mirror. You will not need it.

Looking at cables you see new mirror has all same cables as old one with same colours but not pin 7 magenta-yellow which is climate sensor.

Old mirror also has bigger metal heads in cables. New mirror has too small. Take metal heads from old mirror cabling and put them in the new mirror cables. So pins 1 to 6 are easy. Little mechanical work. Needs experience.

But you need to wire the climate sensor too: power, ground and sensor wire. Old mirror has a cable for this.

Cut out climate sensor cabling and its small 3 pin connector from old mirror. Remove black tape to reveal old mirror cables so you can cut them out full.

Steal power to climate sensor from wire 1 (white) and ground from wire 2 (black) in new mirror cabling. If you open old mirror cabling you see that cable does the same.

Wire middle pin 2 magenta-yellow in 3 pin connector to pin 7 in the 8 pin mirror connector. You can cut pin 7 cable from old mirror cabling and use that.

Finally fit 8 pin connector plastic to new mirror cabling you made, same colour cables to same pins as in old mirror cabling you wrote down earlier.

So then your new mirror should have these cables using the old 8 pin connector:

- pin 1 white
- pin 2 black
- pin 3 grey
- pin 4 yellow
- pin 5 brown
- pin 6 green
- pin 7 magenta-yellow
- pin 8 (empty)

And small connector for climate sensor wired up too:

- black (in pin 1, connected to black pin 2 in 8 pin connector)
- magenta-yellow (in pin 2, connected to magenta-yellow pin 7 in 8 pin connector)
- red (in pin 3, connected to white pin 1 in 8 pin connector)

Connect climate sensor to 3 pin connector and push base plastic back in place.

Do confirm all connections from your car schematics!

Modification for mirror is now done.

See method 1 for how to put it all back in the car. Done!


UPDATE 24.2.2009: SplendidAudi asked me to add following message, where he comments on how to install digital compass mirror in a car without auto-dimming rear-view mirror from factory (see the link in the beginning of this article).

"does your car have three zone climate? if it does you may already have 8 pin connector with power wired to it under wire cover above mirror. or you can steal power and ground from rain sensor power if you have that

digital compass mirrors are always also auto dimming mirrors

i think you need to connect at least mirror cable pins 1 white power, pin 2 black ground to compass/auto dimming mirror to it to work.

three other pins are for auto dimming side mirrors. not needed

one pin, can not remember which, goes to convenience module to turn off dimming mirror when reversed but that may not be mandatory. try with just power

try to see if you have a 8 pin connector under wire cover?"


By SplendidAudi

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