Hi, I have Audi A4, year 2000, 1.8 petrol engine. When I take the key out of ignition the car keeps running and you can drive, however the air conditioning gets switched off as if the car is off completely. Initial reaction was ignition switch, however this was replaced and still did not fix the problem. The only way to switch the car off is to hold the brake down, however when you let it go, the dash board lights will come back on. Than you have to tap the brake in order to get it offcompletely. I had the car in the garage when doing the timing belt but they did not know what it could be. Anyhelp would be much appreciated.