Your Vehicle: 2001 Ford Escort ZX2 L4-2.0L DOHC VIN 3
 
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  Control Components  
 

A/C Passenger Compartment Components Part 1
  

A/C Passenger Compartment Components (Legend) Part 2
  

The manual climate control system heats or cools the vehicle interior depending on the function selector position and the temperature selected. The function selector position determines heating or cooling and air distribution. The temperature control setting determines air temperature.

The manual climate control components are used to:

  • select air inlet source (outside or recirculated).
  • select blower motor speed.
  • select discharge air temperature (temperature blend).
  • select discharge air location (defrost, panel, floor).
  • select A/C compressor clutch operation.

  

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 positive voltage (B+) to the A/C clutch circuit and the blower motor control circuit.
  • The temperature selection is accomplished with a manually-controlled blend door actuator that controls positioning of the temperature blend door. Movement of the control knob from COOL (Blue) to WARM (Red) causes a corresponding movement on the air temperature control door and determines the temperature that the system will maintain.
  • The blower motor switch controls blower motor speed by adding or by passing resistors in the heater blower motor switch resistor.

The following systems are grouped together into a single integrated control panel:

  • in-vehicle entertainment
  • clock
  • heated back window
  • climate control

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 positive voltage (B+) to the A/C clutch circuit and the blower motor control circuit.
  • The temperature selection is accomplished through cable controlled positioning of the temperature blend door located in the heater core housing.
  • The blower motor switch controls blower motor speed by adding or by passing resistors in the heater blower motor switch resistor.

  

Blower Motor Switch Resistor
The heater blower motor switch resistor has the following features:

  • The assembly is located on the passenger side of the plenum assembly behind the glove compartment.
  • Three resistance elements are mounted on the resistor board to provide four A/C blower motor speeds.
  • Depending on the heater blower motor switch position, series resistance is added or bypassed in the A/C blower motor circuit to decrease or increase A/C blower motor speed.
  • An overheating protective device (thermal limiter) will open the resistor coil circuit when the temperature reaches 121°C (250°F) interrupting the blower motor operation in all speeds except HI.
  • The thermal limiter cannot be reset and is not serviceable.

The heater blower motor switch resistor has the following features:

  • The assembly is located on the passenger side of the A/C evaporator housing behind the glove compartment.
  • Three resistance elements are mounted on the resistor board to provide four A/C blower motor speeds.
  • Depending on the heater blower motor switch position, series resistance is added or bypassed in the A/C blower motor circuit to decrease or increase A/C blower motor speed.
  • An overheating protective device (thermal limiter) will open the resistor coil circuit when the temperature reaches 121°C (250°F) interrupting the blower motor operation in all speeds except HI.
  • The thermal limiter cannot be reset and is not serviceable.

  

Constant Control Relay Module
The constant control relay module uses a combination of relays and solid state switches to control the following systems:

  • engine cooling fan
  • A/C clutch
  • fuel pump
  • powertrain control module power

The powertrain control module can interrupt A/C compressor operation through the constant control relay module under the following conditions:

  • during engine start-up
  • Wide Open Throttle (WOT)
  • low engine idle conditions
  • excessively high engine temperatures

Heated Back Window Switch
The heated back window switch is a component of the Integrated Control Panel (ICP) and cannot be repaired separately. Refer to windows and Glass/Heated Glass Element to repair the heated back window system.