Preliminary Information

IMPORTANT THE INFORMATION CONTAINED IN THE CHARTS CAN GIVE A INDICATION OF A SYSTEM FAULT, HOWEVER A INCORRECT DIAGNOSIS OF THE SYSTEM IS POSSIBLE.

Diagnostic Flow Chart

This chart is the starting point for verifying and diagnosing all air conditioning and HVAC control related complaints. It represents the correct path to follow in response to a customer complaint or condition.

Preliminary Checks

This step covers all physical and visual inspections of interior and underhood components. Many problems can be detected by thorough inspection. Failure to perform this step could result in wasted time proceeding further down the flow chart.

Vehicle Set-Up and Performance Test

To run an air conditioning performance test the vehicle must be set-up according to the service manual instructions. Improper vehicle set-up will result in inaccurate pressure and temperature readings.

General and Specific System Condition Charts

These charts were developed in a wind tunnel by producing known system problems and recording pressures and temperatures. The tests were then validated using the same vehicle set-up in a service environment. To find your system problem, compare the performance test readings to the readings on the charts for your ambient temperature. There is variance in readings between systems of different vahicles, however, the target areas have been developed to accomodate these changes.

Compressor Control Test

This is designed to evaluate the compressor's ability to change displacement with varying heat loads.