Need to get my wifes car heater blower working again.

SOURCE: clicking noise behind ac /heater control on dash

the problem is with the blend door it controls the blend of hot and cold air. there is a small electrical motor that can go bad or they can hang up
you will probally have to take some covers off to find out whats going on

SOURCE: My 1996 Lincoln Town car

To fix the AC unit which blows hot air all the time. Seems like you have a small leak in the system or the AC compressor has gone out. Suggest you try recharging the unit. Make sure you have the correct R-22 or 134A freeon. If this work for a few days then have the leak fixed, if this doesn't work replace the compressor. Check Ebay for the compressor i obtained one for $100.00. Cost $450 at Auto Zone.

SOURCE: what is the function of the idle speed control valve?

The idle air control (IAC) valve assembly on a combustible engine monitors and manipulates the amount of controlled air moving around the throttle plate. The IAC valve is managed by the electronic control module (ECM) of the engine, which calculates the position of the IAC valve. Voltage pulses called counts extend and retract an internal conical-tipped shaft called a pintle inside the IAC valve. When the pintle is extended, the cone-shaped tip positions itself closer to the air inlet and restricts the amount of air allowed to pass through the throttle, building up more air around the throttle plate to increase the rpms of the engine. When the pintle is retracted, it moves away from the inlet and allows more air into the throttle away from the throttle plate, decreasing the rpms. The IAC valve operates and adjusts constantly while the engine is running to help prevent the engine from stalling or surging. This will not cause the engine to misfire!! Hopefully this helps

SOURCE: 1999 town car blower motor resistor.....maybe?

The Blower Motor Resistor is a common problem in your car but not for the problem you describe. When the Heat/AC won't blow on all speeds, the blower motor resistor is at fault. When air won't blow out of vents, bi-level, or floor the problem is the blend door actuator. This is vacuum driven and diverts the air to where you select. When air will only blow from one place (usually the defrost) then the blend door actuator is the problem. This can sometimes be corrected if there's a vacuum leak (usually under the hood in front of the passenger you'll find the vacuum line and can trace it backward to find a leak). If no leak can be found, the blend door actuator itself is defective and needs replacement.

SOURCE: Heater wont blow hot air in my 1998 Lincoln Navigator

the computer that controls the deflector motor are not responding and opening the door for heat, I'm sure you have climate control,check the temp setting sensor to the computer input first