Q&A

I'd been having an intermittent problem with my car deciding to suddenly not restart after short drives. And a couple weeks ago it quit starting all together. The mechanic had it for a week, but only ever replaced one fuse for the computer, and then couldn't duplicate the problem. There are no codes coming back, but at one point in time the mechanic got an error that the air bag wasn't communicating with the computer, but even that error went away. I can hear the fuel pump kicking on, i've got compression and fire as well. I've replaced the battery, and the positive battery cable (which was in dire straits), the starter is fine...My auto knowledge is limited and i've simply ran out of ideas, I hate to take it back to the mechanic because they can't find the problem either. I also noticed that when the car suddenly decides it doesn't want to start, the radio will magically come on even with the key out, and if you turn the key on, the defrost/ac/fan will give a yellow flashing light and will become inoperative. Anyone have any ideas on something specific, or does it sound like a short, i'm not used to audis, and I am flat out stumped