Nissan Repair: Heater, nissan 240sx, heater hoses

Question
I have a 1991 Nissan 240SX. Driving it on vacation for the holidays the heater was working fine, in fact was too hot at times. All the sudden it went cold, not gradually but instantly. Now it will not blow hot at all just very cold air. Please help. No one seems to know what would make it do that. I need to get this repaired before I prepare to head home in a few days. FREEZING OUTSIDE!!

Answer
Deitra,

Either the blend door is stuck on cold and that would be the control actuator or the door actuator under the dash.  To check this remove the glovebox and check for actuation when you run the control from hot to cold.  Otherwise, you might check to see that the heater hoses are warm at the firewall to make sure nothing is plugged.  And, that the temperature on the gauge is reading normal and not cold.  A stuck thermostat can cause the heater not to blow warm air.