Check the thermostat, heater core and the air blend door-
March, 8, 2012 AT 4:55 PM
Thermostat could be stuck open, heater core clogged and air blend door stuck in the cold position-also check heater control valve
March, 25, 2012 AT 3:04 AM
Check the vacuum hoses/capilary hoses that come from the engine.
Theses are in the wire loom harness. You may have to cut the black tape off the wire loom. These get brittle and break over time. A quick trip to the salvage yard or parts store can get some replacement hose. If the vacuum doesnt open the heater door the air from the heater core/evaporator core wont blow through.
March, 27, 2012 AT 5:36 AM
Kellerke: Also check to make sure there is coolant in the system.