1997 ford taurus the heat does not work but ac does. I can not find detailed drawings of the unit. A repair manual talks about removing the steering wheel. I don't think I need to go that far. I replaced the thermostat but that's not the problem.

Disconnect the control unit wire harness and then plug it back in. Should do the trick, corrosion. Disconnect negative side of battery first.

Air Temperature Control Blend Door Failure No Heat or no AC (dependes on where door sticks)

In all modern cars there is a tiny DC electric motor driven gear drive that moves a plastic door that blends heated and cooled air from the AC and the heater core, this is called (interestedly enough) the air temperature control blend door actuator. The motor that moves this door fails because the door starts sticking from warping, most common complaint is no heat but it can be no AC as well. To replace these parts (blend door and blend door actuator) you must remove the entire dash from the car. Always have this problem confirmed by a dealer or qualified repair shop as it is a very expensive repair.

Other causes of no heat in the cabin are engine thermostats that are stuck open (engine runs cold) or air bubbles in the cooling system.

Manuals are available at most auto stores...price from 20-40 dollars

Are you talking the ccrm? Those relays are soldered into the circuit board. Some of my ford info, says if the relays in the diagram have no terminal pin numbers, the relays are soldered into the circuit board, you can't pull it out. Sometimes It may be possible to use an external relay, wire it up properly and it should work.
If your talking about the ccrm/ constant control relay module, I'd probably just replace it, if that is the problem.
If your talking about a different relay then, I need more info?

it could be expensive i wouldnt buy it becuase ac can easily cost you 1500 depending on problems but its not worth the risk

Do you mean the heat/AC fan????
Passenger compartment fuse panel fuse #13 it's a 5 amp fuse
The fuse panel is
located below and to
the left of the steering
wheel by the brake
pedal. Pull the panel
cover outward to
access the fuses.

FUSE PANEL is located below and to the left of the steering wheel by the brake pedal. Remove the panel cover to access thye fuses; this and other details can find in the 1999-Ford-Taurus-Owners-Manual (page 126 and next).

Hope this help (remember comment and rated this).

Ford Taurus/Sable 1996-1999 Repair Guide
Flashers - REPLACEMENT

Check your flashers:



Fig. Fig. 1: Flasher assembly mounting

1. Disconnect the negative battery cable.
2. Locate the flasher assembly under the driver's side of the instrument panel and remove the flasher retaining screw.
3. Detach the flasher from the connector and remove the flasher from the vehicle.

To install:

1. The installation is the reverse of the removal.

Other details can find in the Ford-Taurus Owners Manual (page 124 and next)

Hope helps with this (remember rated this).

i would say your ac is low on gas, [plain and simple]but if your switch is not working then the a/c wont work.adrian;;;;

it sound as if the drive belt broke or the timing belt try these websites to see if you can get some more information www.alldatadiy.com and www.autozone.com and www.taurusclub.com if all fails stop by your local library and get your hands on a Haynes auto repair manual for your car.