Electrical System

The electrical system consists of the blower motor, blower speed switch, blower on/off and clutch switch (integral with the control assembly), blower resistor with a thermal limiter, clutch cycling pressure switch, the magnetic clutch and the fuses and wiring to complete the circuit. Models equipped with the 2.3L engine also have an electro-drive engine cooling fan.

The blower motor is installed in the blower housing which is located behind the air inlet duct at the right end of the evaporator assembly. The motor and mounting flange are serviced as an assembly and should not be disassembled.

The blower (FAN) speed switch is mounted on the control assembly and, with the blower resistor, allows the selection of four blower speeds. This switch does not turn the blower off.

The blower motor resistor is installed in the rear face of the lower half of the evaporator case and is located behind the glove compartment. The resistor is used in conjunction with the blower speed switch to obtain the four blower speeds.

The resistor assembly also contains a thermal limiter which is used as a temperature protecting fuse. The thermal limiter is located a preset distance from the resistor coils. If the temperature of the thermal limiter reaches 121°C (250°F), the limiter contacts will open interrupting the blower motor circuit for all blower speeds except HI.

Blower Motor Resistor Assembly with Thermal Limiter

The clutch cycling pressure switch and the clutch field coil are connected in series to control compressor operation. The pressure switch is mounted on the suction accumulator/drier and closes when the pressure on the low side of the refrigerant system reaches approximately 310 kPa (45 psi). The switch will open when the system pressure drops to approximately 172 kPa (25 psi). In ambient temperatures below approximately 7°C (45°F), the pressure switch will not allow compressor operation because of low system pressures.

On vehicles equipped with the 2.3L engine, an electro-drive cooling fan is used. When the function selector lever is in either A/C position (MAX or NORMAL), the cooling fan is controlled by the opening and closing of the clutch cycling pressure switch. Power to the fan is through a controller module as controlled by the pressure switch and the cooling fan temperature switch. If the engine coolant temperature exceeds approximately 105°C (221°F), the cooling fan temperature switch closes and the fan will operate continuously until the engine coolant temperature drops below 105°C (221°F).

Electro-Drive Fan Controller—2.3L Engine