System Overview

Many of the components in the electronic automatic air conditioning system are the same as the components used in the manually controlled air conditioning system. The following paragraphs give a brief explanation of components specific to the electronic automatic air conditioning system. For information, diagnosis, and service of the refrigerant and air distribution systems.

The electronic automatic air conditioning system has a rheostat controlled motor (temperature door motor) to position the temperature door, instead of a temperature control cable as used on manually controlled air conditioning systems.

The electronic automatic air conditioning system control head has an LCD readout which will display outside temperature, temperature setting, and diagnostics.

The computerized A/C programmer receives input from several on-vehicle sensors, the CCM, also temperature and mode requests from the control head. The information input to the programmer is processed and used to control the electronic automatic air conditioning system.

Three sensors, specific to the electronic automatic air conditioning system, provide input to the programmer:

OUTSIDE AIR (AMBIENT) TEMPERATURE SENSOR

This sensor is located on the right-hand side of the radiator upper support and senses the temperature of the air outside the vehicle.

The sensor input is filtered by the HVAC programmer to minimize false ambient temperature readings displayed on the HVAC control head. Temperature updates are dependent on the following conditions:

^ Vehicle speed is greater than 25 mph (41 km/h) for more than 3 minutes or 45 mph (72 km/h) for 1 1/2 minutes. Updates will occur on a consistent basis as long as vehicle speed stays above 25 mph (41 km/h).
^ When speeds fall below 25 mph (41 km/h) no updates occur.
^ If the ignition is turned "OFF" then "ON" within 3 hours and the current ambient temperature is less than what was stored upon ignition "OFF."
^ If the ignition is "OFF" for more than 3 hours, current ambient temperature is stored immediately.

IN-VEHICLE TEMPERATURE SENSOR

This aspirator type temperature sensor is located in the air conditioning outlet directly in front of the passenger seat and senses the in-vehicle temperature.

SUN LOAD SENSOR

The sun load sensor is located on a removable grille in the center of the I/P upper trim pad. This sensor measures the amount of heat generated from the sun shining in the vehicle.