Control System Inputs - Electronic Automatic Temperature Control (EATC)

Heating Ventilation Air Conditioning (HVAC) Module 

The heating ventilation air conditioning (HVAC) module, located in the instrument panel, has the following features:

• A blower speed override control for manual input
• A vacuum fluorescent display for displaying set temperature, ambient temperature, function and DTCs
• An On-Board Diagnostic (OBD) feature to supply the technician with DTCs. These DTCs direct the technician to the inoperative component

Steering Wheel Audio/Climate Control Switch 

The steering wheel audio/climate control switch, located on the right side of the steering wheel, allows the driver to adjust the passenger compartment temperature setting and manually override the blower motor speed setting. For removal and installation of the steering wheel audio/climate control switch, refer to INFORMATION & ENTERTAINMENT SYSTEMS article.

Ambient Air Temperature Sensor  

The ambient air temperature sensor:

• is located in front of the A/C condenser core near the center of the vehicle.
• contains a thermistor which measures the temperature of outside air as a resistance and sends that reading to the HVAC module.

In-Vehicle Temperature Sensor  

The in-vehicle temperature sensor operates in the following manner:

• A thermistor in the in-vehicle temperature sensor measures air temperature inside the passenger compartment
• An automatic temperature control sensor hose and elbow is connected between the A/C evaporator housing and the in-vehicle temperature sensor
• The automatic temperature control sensor hose and elbow takes air from the A/C evaporator housing air stream to create a suction in the in-vehicle temperature sensor
• The suction draws in-vehicle air into the in-vehicle temperature sensor and across the thermistor

Sunload Sensor 

The A/C sunload sensor:

• is located on the top RH side of the instrument panel above the glove compartment.
• contains a photovoltaic diode that is sensitive to light.