Temperature Controls
TEMPERATURE CONTROL SYSTEMThe temperature control system is dependent upon the interaction of the following electronic components:
BODY COMPUTER MODULE
Description and Operation
TEMPERATURE INPUTS
These inputs are monitored by the Body Control Module (BCM) to control the climate control system. These temperature values are sent to the BCM via thermistors which decrease in resistance as they get hotter. Each of these thermistor-type sensors is listed below:
1. IN-CAR TEMPERATURE SENSOR
Description and Operation
2. OUTSIDE TEMPERATURE SENSOR
Description and Operation
3. COOLANT TEMPERATURE SENSOR
Description and Operation
4. A/C HIGH SIDE TEMPERATURE SENSOR
Description and Operation
5. A/C LOW SIDE TEMPERATURE SENSOR
Description and Operation
6. SUNLOAD SENSOR
Description and Operation
LOW REFRIGERANT PRESSURE SWITCH
Description and Operation
CLIMATE CONTROL FEATURES
The program number is a number calculated by the BCM to express the amount of heating or cooling required to meet the desired inside temperature. This number is based upon the following variables:
- Set temperature on Climate Control Panel
- Outside temperature
- In-car temperature
- Sunload sensor
The calculated program number is used to determine the proper air delivery mode and blower speed, and is a factor in determining the air mix valve position. A program number of 0 represents maximum system cooling and 99 represents maximum system heating. As the in-car temperature nears the desired set temperature, the program number will begin to approach a value appropriate for maintaining comfort based upon current ambient conditions.
The program number can be observed while in the diagnostic mode. A self diagnostic feature allows the service technician to manually override the calculation of the program number to observe system operation throughout the working range.