You have an alignment problem in the rear suspension, check for worn control arm bushings or a bent control arm (You might not see any bends without a straight edge run along the tubes, they should be perfectly straight.), if all still looks good and the Struts are in good shape, get the car aligned and have the technician pay close attention the the rear alignment specs.
If the HVAC is cintrolled by an Automatic Temperature Control Panel (Climate Control) those panels have been known to develop intermittant failures, usually a cold solder joint somewhere in there is the culprit, finding it is another story. Usually the best thing to do is see if you can fund a panel at a wrecking yard and replace it, it's cheaper from them than ordering the part from a dealer. (I got quoted 450 for one at a dealer!)