DTC B1239 or DTC indicator 3: An Open or Short in the Mode Control Motor Circuit (Front)

Clear the DTCs with the HDS.
Turn the ignition switch to LOCK (0) and then back to ON (II).
Do the self-diagnostic function with the HDS (see HOW TO USE THE SELF-DIAGNOSTIC FUNCTION WITH THE HDS ) or the HVAC control unit (see HOW TO USE THE HVAC CONTROL UNIT SELF-DIAGNOSTIC FUNCTION WITHOUT THE HDS ).
Check for DTCs.
Is DTC B1239 or 3 indicated?

YES -Go to step 5.

NO -Intermittent failure, check for loose wires or poor connections in the front mode control motor circuit.
Turn the ignition switch to LOCK (0).
Test the front mode control motor (see RECIRCULATION CONTROL MOTOR TEST ).
Is the front mode control motor OK?

YES -Go to step 7.

NO -Replace the front mode control motor (see FRONT AIR MIX CONTROL MOTOR REPLACEMENT ).
Disconnect the front mode control motor 7P connector.
Disconnect HVAC control unit connector A (24P).
Check for continuity between the following terminals of HVAC control unit connector A (24P) and the front mode control motor 7P connector.
24P: 7P:

No. 4 No. 7

No. 6 No. 6

No. 7 No. 5

No. 8 No. 4

No. 9 No. 3

Fig 1: Checking Continuity Between Terminals Of HVAC Control Unit Connector A (24P) And Front Mode Control Motor 7P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 10.

NO -Repair an open in the wire(s) between the HVAC control unit and the front mode control motor.
Check for continuity between body ground and HVAC control unit connector A (24P) terminals No. 6, No. 7, No. 8, and No. 9 individually.

Fig 2: Checking Continuity Between Body Ground And HVAC Control Unit Connector A (24P) Terminals No. 6, 7, 8 And 9
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Repair a short to body ground in the wire(s) between the HVAC control unit and the front mode control motor.

NO -Go to step 11.

Check for continuity between HVAC control unit connector A (24P) terminals as follows.

From terminal	To terminals
6	7, 8, 9
7	8, 9
8	9

Is there continuity between any of the terminals?

YES -Repair a short in the wires.

NO -Go to step 12.

Turn the ignition switch to ON (II), and check the same terminals for voltage to body ground.

Fig 3: Checking HVAC Control Unit Connector A (24P) Terminals For Voltage To Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there any voltage?

YES -Repair a short to power in the wire(s) between the HVAC control unit and the front mode control motor. This short may also damage the HVAC control unit. Repair a short to power before replacing the HVAC control unit.

NO -Check for loose wires or poor connections at HVAC control unit connector A (24P) and at the front mode control motor 7P connector. If the connections are good, substitute a known-good HVAC control unit, and recheck. If the symptom/indication goes away, replace the original HVAC control unit (see HVAC CONTROL UNIT REMOVAL/INSTALLATION ).