Oldsmobile/Buick Repair: heater problem need an opinion, dual control system, vacuum problem

Question
For some reason only the passenger side of my car would blow heat.The drivers side and floor ducts would blow cold air. Now it seems like warm air is blowing at all. Could you please give aidea on what i should do to fix the problem. THE car is an 92 olds 98 regency elite. Thank you for your answer. It will be greatly appreciated

Answer
Hi
If its a dual control system (Driver and passenger can control temp) Then I would HIGHLY suspect either the HVAC control module OR a vacuum problem, OR a faulty temp. actuator on the non responsive side.
If it is NOT a dual control system, I would believe the heater core MAY be partially restricted. You could attempt to disconnect heater hoses from core, and blow LOW PRESSURE (15-30 psi) air through the core.
I hope this helps.
Good Luck
Pawl