Hyundai Repair: Intermittent A/C and Heater, hyundai accent, blower fan

Question
I have a 1997 Hyundai Accent sedan.  This past summer the A/C stopped working.  After giggling the switches it evenutally came on...but eventually got to the point where it didn't come on at all.  Now this winter the heater also seems to have stopped.  Then I discovered that slamming the front passenger door will cause the heater to start working (haven't checked if this fixes the A/C too).  I hate to start tearing into the dash to track down a loose connection.  Do you have any suggestions about where I should look first?  Perhaps this is a common problem and you can tell me exactly where to look?  

Answer
Most likey, the issue is the blower fan motor.  Often, when motors begin to go bad, jarring them will make them begin running again.  That would explain why slamming the passenger door would make it begin running.

The next time the blower doesn't work, unplug the blower motor and install a test lamp into the connector in place of the blower motor.  Turn on the blower (key on).  If the test lamp lights, the blower motor is bad.