A/C System - Manual

Blower

With the Ignition Switch in RUN, voltage is applied to the Blower Motor, through the A/C-Heater Control Assembly in all positions except off. In off, there is no power connection to the motor. With the Blower Motor Switch in HI, ground is connected to the motor for full speed operation. In the intermediate positions, one, two or three resistors are connected between the motor and ground to control current and motor speed.

A/C-Heater

The A/C-Heater Control Assembly and Heater Function Selector Vacuum Valve operate together to control system vacuum and electrical operation. Vacuum motors operate door to direct airflow. The A/C-Heater Control Assembly connects power to the Blower Motor and A/C Clutch Field Coil (5.0L), or Integrated Control Module (2.3L). For 2.3L engines, the A/C Clutch Field Coil is controlled by an Integrated Control Module. This module is regulated by Electronic Engine Control to turn off the A/C System during certain engine operating conditions. However, for 5.0L engines, the A/C Clutch Field Coil is controlled by WOT Cutout Relay, which is energized by a signal from the EEC Module during WOT and other conditions such as high engine coolant temperatures and low or high engine speeds.

The Clutch Cycling Pressure Switch cuts off power to the A/C Clutch Field Coil when suction pressure drops to 24.5 PSI.