Constantly blowing heat

Hi,

The idea that you can't turn the heat off sounds related to what is called the blend air door actuator. This actuator is responsible for the air temperature entering the vehicle.

If I remember correctly, on this year and model, it is controlled by a cable. When you try to change the temp from hot to cold or opposite, do you feel resistance in the slide? If you look at the attached pic, I highlighted where the cable is mentioned. Start by checking to make sure that cable is not broken, disconnected, or loose.

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As far as the blower, first to check if there is power to it. It is located under the hood and mounted on the fire wall of the vehicle.

At the motor, there should be two wires. One is ground and the other is power. Check for both power at one and for continuity to ground on the other.

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If you have power and ground, here are the directions for replacement:

1990 Ford Truck F 350 4WD Pickup V8-7.3L DSL
Blower Motor
Vehicle Heating and Air Conditioning Blower Motor Service and Repair Procedures Blower Motor
BLOWER MOTOR

1. Disconnect battery ground cable.
2. On California models, remove emission module forward of blower motor.
3. Disconnect electrical connector and cooling tube from blower motor.
4. Remove blower motor and wheel attaching screws.

Fig. 27 Disassembled view of blower motor & wheel assembly

Pic 2

5. Move cooling tube aside and carefully remove blower motor assembly from vehicle, Fig. 27.
6. Reverse procedure to install.

With Air Conditioning
1. Disconnect battery ground cable.
2. Disconnect air cooling tube and electrical connector from blower motor.
3. Remove blower motor attaching screws and the blower motor assembly.
4. Reverse procedure to install.

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Let me know if that helps. Also, let me know if the blower motor works on any speed. For example, if it only works on the high setting.

Take care,
Joe

Hi,

As far as the cable, look under the dash where the control unit is located and follow the cable to the blend door to see if it is moving.

If you have no power to the blower motor, first check fuse 9 in the fuse panel. If there it is good, confirm there is power to it. If there is, move to the brown wire with the orange tracer and see if there is power to it at the motor.

See the attached pic.

Let me know.
Joe

Mark,

I attached two pics below. The first one is the wiring schematic for the blower motor/resister. The second one is for the resister location. Note that the manual indicates three possible locations.

Which part number are you referring to?

Let me know.
Joe