I have a 1999 Ford F-150. The heater/Ac does not shift warm to cold. Blower switch/panel switch works okay.?

Question

Blower switch works fine. The switch to shift heat from floor to defrost to panel works okay. It appears that the middle switch is not shifting from heat to cold. Any ideas?

Answer 1

Either the blend door, or blend door actuator has failed. To verify its operation requires removing the actuator itself, to see if the blend door moves freely. If it's broken, the insrtument panel will need to be removed in order to service. Move the temperature selector between full hot, and full cold with the electrical connector still connected to the actuator, but disconnected from the heater box. If it doesn't move, it's either the temperature selector, or something in the circuit, or the blend door actuator itself has failed. E-mail me if you require further information. Hope this helps.

Answer 2

On one of the heater hoses up toward the firewall on the right side you will See a valve that is hooked into the heater hose. This valve has a wire hooked to it that moves a lever back and forth on the valve. It probably has come off. Simply put it back on. You may have to make a minor adjustment on clamp that holds the wire. The wire only sits on the valve lever. Check it out--it's an easy fix

Answer 3

It controls a little door in the vent that mixes cold and warm air. Yours is a pot that controls an electric actuator that determines what position the door is in. It could be a bad control, loose wire, blown fuse, a stuck door or bad actuator.
Why is there always some halfwit that says "Check the thermostat"?

Answer 4

Some are vacuum operated so check the vacuum control mechanism to see if diaphragm is broken.

Answer 5

I would have to say that the door is probably stuck to heat and wont let cool are through.

Answer 6

So, is it blowing hot air or cold air. If it's cold air, get you thermostat checked. Also, check your coolant level