1996 Ford Taurus GL- A/C, Heat, Rear Defroster Fails

[HSRudolph]

I own a 1996 Ford Taurus sedan with 151,000~ miles on it. I recently purchased this vehicle, and all of the following issues I've been having with it have existed since it came into my hands. Any and all help will be deeply appreciated.

1.) When the rotary knob on the dash is turned from 'Vent' to 'A/C', no change can be identified. The air that is blown out is warm, and unchanged from that of the 'Vent' air. Furthermore, the knob seems to freely move between 'A/C' and 'Max A/C', as if there was no division between the two. The wife thinks that the air conditioning worked awhile ago-- when it was cooler. I'm not so certain.

2.) During the winter months (which are quite grueling up here,) the heat in the car seems to work (albeit poorly) to a certain extent. When it is above 20 degrees outside, the heat slowly warms up to a halfway-decent temperature and heats the car. Below 20 degrees, my experience has been that it fails to work almost completely.

3.) The rear defroster simply never works. When the button is pushed, a clicking noise can be heard-- but the light does not turn-on, and the rear window is not defrosted.

Thanks in advance!

[KimMG]

1.) The switch may have failed.
2.) Heater core may be clogged. Heater cores should flushed separately from the rest of the cooling system.
3.) Use a wiring diagram to trace the circuit and test each component.

[KimMG]

"Your help regarding the issues I'm having with my Taurus are deeply appreciated.

Your answer to my first question was "the switch may have failed."

Is there anything I can do to remedy that?" Your quote from PM

If the switch has truly failed, you need to replace it.
If you don't have a repair manual and don't want to buy one. Libraries and schools are good sources for manuals. Many libraries and schools subscribe to online databases that can be accessed from home.
Autozone.com has some technical pages that also may be of help.