DeVille, Eldorado, Seville 1999-2005

Description & Operation


The climate control system automatically regulates and maintains the inside air temperatures from 65-85°F (18-29°C) regardless of the changes in the ambient air temperature. Settings of 60-90°F (16-32°C) provide unregulated heating and cooling.

The heater and A/C control selects a comfort level. The following main components comprise the climate control system:

The heater and A/C programmer, also called the air control module (ACM)
The powertrain control module (PCM)
The temperature sensors
The heating, ventilation, and air conditioning (HVAC) module
The refrigeration system

The climate control system is divided into the following 4 categories:

The general operation
The air delivery system
The refrigeration system
The temperature control system

The refrigeration system contains the following major components:

A compressor 
A condenser 
An evaporator 
An expansion (orifice) tube 
An accumulator 

The following components control the refrigeration system:

The heater and A/C programmer (Control Panel)
The powertrain control module (PCM)
A low-side refrigerant temperature thermistor

The thermistor turns the compressor ON and OFF as required in order to prevent evaporator condensation freeze. The compressor runs only as much as necessary.

During the cooling operating conditions, you may notice slight increases and decreases of the engine speed/power. This characteristic is normal as the system is designed to cycle the compressor on and off in order to maintain the desired cooling.

Avoid breathing the A/C Refrigerant 134a (R-134a) and the lubricant vapor or the mist. Exposure may irritate the eyes, nose, and throat. Work in a well ventilated area. In order to remove R-134a from the A/C system, use service equipment that is certified to meet the requirements of SAE J 2210 (R-134a recycling equipment). If an accidental system discharge occurs, ventilate the work area before continuing service. Additional health and safety information may be obtained from the refrigerant and lubricant manufacturers.

For personal protection, goggles and gloves should be worn and a clean cloth wrapped around fittings, valves, and connections when doing work that includes opening the refrigerant system. If R-134a comes in contact with any part of the body severe frostbite and personal injury can result. The exposed area should be flushed immediately with cold water and prompt medical help should be obtained.