Where is the AC/Heater Control Actuator located?

Are the heater hose from the engine compartment going to the fire wall hot to the touch ? Is the HVAC - heating , ventilation an A/C system manual or automatic ?
Control System Inputs-Manual A/C
Climate Control Assembly
The climate control assembly has three system controls:

• The A/C heater function selector switch combines a vacuum selector valve with two electrical switches to supply battery voltage (B+) to the A/C clutch circuit and the blower motor speed control circuit.
• Temperature selection is accomplished with a potentiometer connected to the electric blend door. Movement of the control knob from COOL (Blue) to WARM (Red) causes a corresponding movement on the air temperature blend door and determines the temperature that the system will maintain.
• The blower motor switch controls blower motor speed by adding or bypassing resistors in the heater blower motor switch resistor.

Control System Outputs-EATC
A/C Blower Motor Speed Control
The A/C blower motor speed control is located on the A/C evaporator housing, in the engine compartment.

• The function of the A/C blower motor speed control is to convert low power signals from the electronic automatic temperature control module to a high current, variable ground feed for the blower motor.
• Blower motor speed is infinitely variable and is controlled by the electronic automatic temperature control module software.
• A delay function provides a gradual increase or decrease in blower motor speed under all conditions.

A/C Electronic Blend Door Actuator
The A/C electronic blend door actuator is located on the top of the plenum housing.

• Its function is to move the air temperature blend door on command from the control assembly.
• The A/C electronic blend door actuator contains a reversible electric motor and a potentiometer. The potentiometer wiper is connected to the actuator output shaft and moves with the output shaft to indicate the position of the air temperature blend door.
• A 5 volt signal is applied to the ends of the potentiometer. The voltage available at the wiper indicates the position of the potentiometer. The expressed value of the actuator wiper voltage is sent to the electronic automatic temperature control module and is matched with the wiper voltage of the module potentiometer. The control module then drives the actuator motor in the direction necessary to make the actuator wiper voltage agree with the control module wiper voltage.

First check your coolant level. If the coolant system is full, then it is probably the passage doors inside the heater/AC case not operating properly. A door or its actuator has a malfunction. Most actuators are vacuum controls, although some are electric motor operated. Turn Heater on and set temp. control on high-this should cause the actuators to respond by opening some inner doors. So when you turn the blower on, air is forced across the heater core (the little coolant filled "radiator" in the case), and warm air comes out the vents. Watch or listen for the actuators to respond when you use the heater controls. There may be several actuators on the heater case, situated all around, but they are on the outside of the case, right near the inner door they operate.

you have to replace the blend (heat/cold) door motor, you can try to remove motor and turn door and try to jam something in door handle slot ,that the part that the motor turns,hope this helps.

ok, missed the part about the rear ac working, the part that causes this is called the air temperature control blend door actuator motor, it is an electric motor driven gear drive that moves the plastic door inside the air ducking to mix or shut off the hot or cold air from the ac evaporator core or the heater core, you will need to replace it.

this problem is caused by the blower motor speed control resistor being defective, it is located next to the blower motor.

Is the heater working? Turn the A.C. off with the car at an idle. Turn the A.C. on and listen for the compressor to turn on. (should hear a click under the hood and the motor should change pitch. If no noise, the compressor is not comming on. The o-rings were bad about leaking on these cars, letting out all the freeon. If there is no freeon, the low pressure switch won't let the compressor run.

The temp blend door rotates between allowing heat through the heater core, or cold air through the a/cevaporator, or a blending of the 2 by being anywhere between the two.

I would check the heater a/c control head first and hope it's just the control head.
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here is a descripton of the system.

Section 12-03A: Air Conditioning, Heater System, Manual, Ranger and Explorer 1996 Ranger and Explorer Workshop Manual
DESCRIPTION AND OPERATION A/C-Heater System, Manual The manual air conditioning/heater system used in these vehicles is a split-case, blend air design. This design includes the following major components:

• An A/C evaporator housing (19850) which is attached to the engine compartment side of the dash panel (01610). This assembly includes: (1) the A/C evaporator core (19860), (2) the suction accumulator/drier (19C836), (3) the A/C cycling switch (19E561), (4) an internal, A/C evaporator core orifice (19D990) located inside the inlet line to the A/C evaporator core, (5) a blower motor (18527), (6) a blower motor wheel (18504), (7) a heater blower motor switch resistor (18591), and (8) the A/C evaporator case (19897).
• A heater air plenum chamber (18471) which attaches to the passenger compartment side of the dash panel. This assembly includes: (1) the outside/recirculating air inlet door, (2) the panel door, (3) the floor defrost door, (4) the temperature blend door, and (5) the heater core (18476).
• Other components which link and/or control the heating and air conditioning systems include: (1) the A/C control (19980), (2) the ducts and registers, (3) the windshield defroster hose nozzle (18490), (4) the control cables, (5) the vacuum lines, (6) the refrigerant tubes and hoses, (7) the A/C compressor (19703), and (8) the A/C condenser core (19712).

The A/C control (19980) assembly consists of three main parts:

• The function selector knob, a vacuum selector valve combined with an internal electrical switch.
• Heater blower motor switch (18578), an electrical switch that provides four speeds of A/C blower motor operation.
• A temperature control knob, which controls the position of the temperature blend door mounted on A/C evaporator housing (19850) assembly.

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Temperature Control
The temperature selector actuates a variable resistance switch. This switch varies the voltage to an electric actuator used to position the temperature blend door. Positioning the temperature control in any position between COOL and WARM causes the temperature blend door to direct more or less outside air through or around the heater core (18476) for whatever proportion of heated or unheated outside air is desired. The air blends together as it leaves the heater core and enters the heater air plenum chamber (18471) for distribution.
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System Airflow Description Air is drawn into the system by the blower motor (18527) through the outside-recirc. door opening. The air is blown through the A/C evaporator core (19860) and then the heater core (18476) (when the temperature control is moved toward the WARM position). When the temperature blend door is in the maximum COOL position, the air bypasses the heater core. When the temperature control is moved to the right, away from the maximum COOL position, air passes through the heater core where it is warmed, and then mixed with the cool air before it is discharged through the registers. OFF
With the function selector in the OFF position, the outside-recirc. door is in the recirculated air position. It is closed to outside air and no air passes through the system. The blower motor is off. MAX A/C
NOTE: No temperature modulation is possible in the MAX A/C position.

In the MAX A/C position, the outside-recirc. air door is in the recirculated air position. All of the air discharges through the panel registers except for a small amount of floor bleed. The A/C compressor (19703) operates in this function control setting.
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You have to almost remove the dash to get this part out.
Removal

1. Disconnect battery ground cable.
   

1. NOTE: Refer to Section 01-12 for instrument panel removal and installation procedure.
   
   Loosen instrument panel (04320) and pull back from cowl.
   

1. Remove A/C electronic door actuator motor electrical connector from bracket on A/C evaporator housing.
   

1. Remove three A/C electronic door actuator motor retaining screws.
   

1. NOTE: The mounting bracket remains in place on the A/C evaporator housing.
   
   Lift A/C electronic door actuator motor vertically approximately 12mm (1/2 inch) to disengage it from bracket and actuator shaft, then pull A/C electronic door actuator motor back toward passenger compartment.
   

The problem may be a faulty blower motor behind the heather core, or a problem with wirings.

ase mechanic:

Sounds like a problem with the front blower motor. there is a blower motor resistor for the front blower motor that controls the speed of the blower and tends to go bad or fry out the blower motor. thats the most likely scenerio since you stated the control head was lighting up and responded to button changes.

Dis you chanfe the blower motor speed controller? It is mounted right near the blower motor itself.... attached to the blower motor via a electric cable.... held in place in it's mounting by 2 screws into the heater AC case