Audi Repair: ABS light, brake light, tachometer to zero, oil can light, and air conditioning, pressure sensor, oil pressure

Question
Hello,
My 1998 A6 has the ABS light come on and stay on, the brake light flashes, the tachometer goes to zero, the oil can flashes, three beeps sound, and the air conditioner stops kicking out cold air. The fan continues to work, but there is no cold air. This problem was intermittent, but now is constant. The oil pressure sensor was replaced. The cluster was checked and no problem was detected. Please respond to what can be tried next.
Thank you.

Answer
hello
this is not something to fix over the mail. I will start with checking the faults in ABS system when the broblem is happen - if you can not talk to the module ( I have seen this many times) ABS module is bad. Then module goes bad , ABS light comes ON and brake light flashes.
There also may be a problem with connection somewhere in the harness. maybe one ground or power splits into systems which do not work , ( need wire diag. by VIN).
this is where I will start.
good luck , Greg