DTC B1344: HTR/Def/Ac Door Movement Fault: Description

Rear junction block (located under rear seat) supplies ignition voltage through circuit No. 141 (Brown wire) to mode actuator. See WIRING DIAGRAMS  .

Instrument Panel Module (IPM) commands actuator to move by supplying voltage on the command line circuit No. 1318 (Yellow wire). Command line voltage and motor actions are as follows:

• 0 volts - Moves toward full hot.
• 2.5 volts - Stops motor.
• 5 volts - Moves toward full cold.

IPM determines actuator position by monitoring voltage on feedback circuit No. 1814 (Yellow/Black wire). A feedback potentiometer supplies regulated 5-volt signal by IPM circuit No. 705 (Gray wire) and a ground from IPM circuit No. 1791 (Yellow wire).

A high feedback voltage of 4-5 volts indicates full hot door position. A low feedback voltage of less than one volt indicates a full cold position. Air mix door actuator operation can be evaluated through scan tool data. DTC will set when ignition switch is in ON position and feedback circuit is open or shorted.