Diagnostic System Check - Process Description - HVAC System - Automatic

The heater-A/C control diagnostic system check is an organized approach to identify problems associated with the heater-A/C control. This system check must be the starting point for any heater-A/C control complaint, and will direct you to the next logical step in diagnosing the trouble condition. The heater-A/C control is a very reliable component and is not likely the cause the malfunction. Most system complaints are linked to faulty wiring and connectors, and occasionally to components. Understanding the heater A/C-control and using the diagnostic tables correctly will reduce diagnostic time and prevent unnecessary pans replacement.