Climate Control Power and Ground Circuit Troubleshooting

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.

Check the No. 3 (7.5 A) fuse in the driver's underdash fuse/relay box.
Is the fuse OK?
1. YES - Go to step 2.
2. NO - Replace the fuse, and recheck.
Disconnect climate control unit connector B (26P).
Turn the ignition switch ON (II).
Measure the voltage between the No. 13 terminal of climate control unit connector B (26P) and body ground.

Fig 1: Measuring Voltage Between No. 13 Terminal Of Climate Control Unit Connector B And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?
1. YES - Go to step 5.
2. NO - Repair open in the wire between the No. 3 fuse in the driver's underdash fuse/relay box and the climate control unit.
Turn the ignition switch OFF.
Check for continuity between the No. 15 terminal of climate control unit connector B (26P) and body ground.

Fig 2: Checking For Continuity Between No. 15 Terminal Of Climate Control Unit Connector B And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Check for loose wires or poor connections at climate control unit connector B (26P). 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.
2. NO - Check for an open in the wire between the climate control unit and body ground. If the wire is OK, check for poor ground at G401.