A/C & Fan Controller Module

The A/C and Cooling Fan Controller Module is operated by the ECA, the coolant temperature switch and the stop-lamp switch. The controller module provides an output signal which controls operation of the A/C compressor clutch and the engine cooling fan.

The controller acts similar to a W.O.T. switch in controlling these devices. The signal for switching on the A/C compressor comes through the clutch cycling pressure switch to the controller module. The module then applies the operating voltage to the compressor clutch. During periods of W.O.T. operation, the ECA signals the controller to turn off the voltage to the compressor clutch.

This W.O.T. signal from the ECA also interrupts the voltage applied to the engine cooling fan if coolant temperature is below 221°F (105°C). The engine coolant temperature switch grounds the controller module if engine temperature exceeds 221°F (105°C). This ground signal overrides the ECA W.O.T. signal, preventing the cooling fan from shutting off at high temperature.

The ECA also contains a time-out feature for the W.O.T. signal. After about 30 seconds, the W.O.T. signal is stopped whether or not the W.O.T. condition has ended. Recycling from W.O.T. to part throttle and back to W.O.T. again will shut off the A/C for 30 seconds.

Stepping on the brake (auto. trans. models with power brakes) also interrupts voltage to the A/C compressor clutch and engine cooling fan for about 3-5 seconds. Battery voltage supplied through the stop-lamp switch is applied to the controller module.