Dual/Electronic Automatic Temperature Control Module - Diagnostic Methods

WARNING: This page is about a different car, the 2003 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.

The dual/electronic automatic temperature control system must be diagnosed by first retrieving any DTCs, if present.

An on-demand (hard fault) DTC indicates that the fault is currently present. An on-demand DTC suggests a wiring fault, disconnected connector, or component failure.
A continuous (intermittent) DTC alone (corresponding on-demand DTC is not present) indicates that the fault is an intermittent condition and may not be currently present. A continuous only DTC suggests a poor wiring connection, loose pin or terminal, or intermittent component failure.

On-demand (hard fault) or continuous (intermittent fault) DTCs can be retrieved using a diagnostic tool. If using a diagnostic tool, refer to the diagnostic tool operating manual.

On-demand DTCs can also be retrieved by carrying out the DUAL/ELECTRONIC AUTOMATIC TEMPERATURE CONTROL MODULE SELF-TEST . To retrieve and/or clear continuous DTCs, carry out the DUAL/ELECTRONIC AUTOMATIC TEMPERATURE CONTROL MODULE - RETRIEVE CONTINUOUS DTCS procedure. Always carry out the DUAL/ELECTRONIC AUTOMATIC TEMPERATURE CONTROL MODULE SELF-TEST before retrieving continuous DTCs.

If no DTCs are present, GO to SYMPTOM CHART for the appropriate diagnostic action.