A4 2.8L. 1999. My heat/ac control is not responding when i press any button on it. It is intermittant problem in that sometimes will not turn on and sometimes it will not turn off. It almost seems like the buttons are not getting power or there is some sort of short in the face. The first question is what can be done about the unit that is in the car? secondly where is a good place to find a control module? And lastly, what tips are there for getting the module out of the dash? thanks in advance. j.p.