AC/Heater Control Problems...Help!

Problem must be either the control or the cable unless something broke at the blend door. Maybe the cable got disconnected from the blend door. The cable is replaceable and has an initial adjustment before installation.

Here are some Ford instructions:

Temperature Control Cable

Removal

1.) Remove control assembly from instrument panel.
2.) Disengage temperature control cable from cable actuator on control assembly.
3.) Disconnect temperature cable from plenum temperature blend door crank arm and cable mounting bracket.
4.) Note cable routing and remove cable from vehicle.

Before Installation

1.) Insert the blade of a small pocket screwdriver into the wire end loop (crank arm end) of the control cable (Fig. 7).
2.) Grip the self-adjusting clip with pliers and slide it down the control wire (away from the end loop) approximately 25.4mm (1 inch).
3.) Install the cable assembly. Refer to Control Assembly and Temperature Control Cable Removal and Installation.
4.) Rapidly rotate the control knob to its fully warm position. This will position the self-adjusting clip.
5.) Check for proper control operation.


Temperature Control Cable

The temperature control cable is self-adjusting with the rapid rotation of the temperature control knob to its fully WARM position. To prevent kinking of the control cable wire, a preset adjustment should be made before attempting to perform the self-adjustment operation. The preset adjustment may be performed either in the vehicle, with the cable installed or before installation (Fig. 7).


Installation

1.) Check to ensure self-adjusting clip is at least 25.4mm (1 inch) from end loop of control cable. Refer to Adjustments.
2.) Route cable behind instrument panel and connect control cable to mounting bracket on plenum.
3.) Install self-adjusting clip on temperature blend door crank arm.
4.) Engage cable end with cable actuator on control assembly.
5.) Install control assembly in instrument panel.
6.) Turn temperature control knob all the way to the right (WARM) to position self-adjusting clip on control cable.
7.) Check temperature control knob for proper operation.
8.) Check system for proper operation.

After Installation

1.) Move the control lever to the COOL position.
2.) Hold the crank arm firmly in position, insert the blade of a small pocket screwdriver into the wire loop and pull the cable wire end through the self-adjusting clip until there is a space of approximately 25.4mm (1 inch) between the clip and the wire end loop (Fig. 7).
3.) Rapidly move the control knob to its fully warm position to position the self-adjusting clip.
4.) Check for proper control operation.

Diagram courtesy of Tmoss & Stang&2birds


See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

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http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

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http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

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http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

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http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

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