2006 Audi A8 Quattro car button
 

All buttons work except car button You can push it down but nothing happens Any idea how to fix it? Cant get to a lot of functions because of it

Might need the PCB cleaning or replacing due to a spilled drink.
To remove, you take out the ashtray insert and remove screws. Remove ashtray, more screws IRRC, then it unclips from the climate control end and is hooked in at the armrest end. Lots of plugs to unplug.
Once in the house you can take the PCB out (more screw - wash it under the hot tap, shake dry and then flush with propan-2-ol.
https://cpc.farnell.com/pro-power-ch...4?st=isopropyl (use at least half of the can.)
Shake dry and you can use straightaway and test. If still faulty, get a new PCB or replace the microswitch.