DTC Indicator L: An Open Or Short In The Mode Control Motor Circuit

WARNING: This page is about a different car, the 2006 Acura MDX, 2005 Acura MDX, 2004 Acura MDX, and 2003 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.

Test the mode control motor (see MODE CONTROL MOTOR TEST ).
Does the mode control motor test OK?
1. YES - Go to step 2.
2. NO - Replace the mode control motor.
Disconnect the mode control motor 7P connector.
Disconnect climate control unit connector B (26P).
Check for continuity between body ground and climate control unit connector B (26P) terminals No. 1, 5, 6, 7, 8, 10, and 11 individually.

Fig 1: Checking For Continuity Between Body Ground And Climate Control Unit Connector B (26P) Terminals No. 1, 5, 6, 7, 8, 10
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Repair any short to body ground in the wire(s) between the climate control unit and the mode control motor.
2. NO - Go to step 5.
Turn the ignition switch ON (II), and check the same terminals for voltage.

Fig 2: Checking Terminals For Voltage
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there any voltage?
1. YES - Repair any short to power in the wire(s) between the climate control unit and the mode control motor. This short may also damage the climate control unit. Repair the short to power before replacing the climate control unit.
2. NO - Go to step 6.

Turn the ignition switch OFF, and check for continuity between following terminals of climate control unit connector B (26P) and the mode control motor 7P connector.

TERMINALS REFERENCE

26P:	7P:
No. 1	No. 7
No. 5	No. 6
No. 6	No. 5
No. 7	No. 4
No. 8	No. 3
No. 10	No. 2
No. 11	No. 1

Fig 3: Checking For Continuity Between Terminals Of Climate Control Unit Connector B

Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Check for loose wires or poor connections at climate control unit connector B (26P) and at the mode control motor 7P connector. If the connections are good, substitute a known-good climate control unit, and recheck. If the symptom/indication goes away, replace the original climate control unit.
NO - Repair any open in the wire(s) between the climate control unit and the mode control motor.