rear air unit has a air blending door solenoid, and is probably out. or broken making a clicking noise
because it is broken
Need to check the fan.
The fan is not working.
heater core....
Flush your radiator coolant and replace thermostat
No the out side fan is for venting heat away fromt he unit.
you have a vac. leake or the oneway check valve is not working.....
warm air, the heat is what is being taken out of the inside of the house.
If you have the lack of heat in your vehicle start by checking the heat core
heat and a/c barley blowing in back?
Car not blowing air or heat
On my Son's 98 expedition we found that the A/C was staying engaged all the time we disengaged the A/C clutch and now we have plenty of heat.