I Have A/C but no heat.

The problem might not be the switch, it might be the heating core that is in the dash. It is essentially a radiator that is under the dash that circulates the hot coolant that the heat is generated from.

you have to switch out the heater core under your dash...but beware, its quite messy.

make sure the heater tap/mixer is working. it controls the flow of coolant from the engine to the heater core. That'd be my first guess...

I would have thought it was the heater core too but I have A/C all the time which is what led my mechanic to believe it was the switches.

I didn't quite phrase my problem correctly. I have A/C all the time!

umm... Is it just cold air(outside air) or is the a/c compressor actually on? Do you hear any noises(the compressor catching) from the engine bay when you switch from a mode where the a/c runs to one where is doesn't? (I think it's the far right nob on the center console that does this(have the temperature nob on cold)) (Anyone have a wiring diagram for this car, I'm not familiar with the system and would like to have something to look at, to help figure out whats wrong)

it could be one of the linkages that attach to the blend door that switches airflow from the heater core to the evaporator. if that has broke even if the switches work the blend door will not move.

my best guess its the heater control valve that controls the flow of the coolant to the heater core is stuck shut, either it needs attention to the linkage or replaced, it would sure be a reason why you can't switch from a/c to heat, some are in the engine compartment, and most are next to the heater core, if it was the heater core it would be leaking or it would be blocked making your car overheat, i just checked and the heater control valve on your car is a direct from ford so you have to go to a ford dealership to purchase one if you plan on tackling it yourself.

Try running the ac with heat applied. If the a/c discharge temp drops you have coolant flowing to and through your heater core. Then the problem would most likely be electrical, but the possiblty of a vacuum concern could be there as well. If now rise in the temp of the air felt with heat applied, then your coolant shut off valve me be stuck closed.

is their a thermostat in your car,if your heater core was bad your windshield would fog up and you would smell collant have the thermostat checked it is eather been taken out or stuck open.

I fixed it. Process of elimination removed hoses from heater core on fire wall attached heater hose and flushed with cleaner forwards and backwards. heater core was clear and not plugged. Put my mouth on the connection and verified entire system would circulate. Wasn't over heating but I replaced the heater thermostat. Still no hot air. Flushed entire system It turned out to be the cable from the heater thermostat switch center dial. The cable goes to a gate that wasn't connected. Connected it it WAMO I got heat. My center dail is still broken and striped but with care it can be turned. If your is past repair you could turn with a pair of pliers clockwise. its uder the sterring wheel on the side of the heater core assemble box. It a metal prong sticking out.