Climate Control Power and Ground Circuit Troubleshooting

Check the No. 30 (7.5 A) fuse in the under-dash 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 A (20P).
Turn the ignition switch ON (II).
Measure the voltage between the No. 1 terminal of climate control unit connector A (20P) and body ground.

Fig 1: Measuring Voltage Between No.1 Terminal Of Climate Control Unit Connector A (20P) & 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. 30 (7.5 A) fuse in the under-dash fuse/relay box and the climate control unit.
Turn the ignition switch OFF.
Check for continuity between the No. 3 (Canada) or No. 6 (USA) terminal of climate control unit connector A (20P) and body ground.
Canada

Fig 2: Checking Continuity Between Terminal 3 Of Climate Control Unit Connector A (20P) & Body Ground - Canada
Courtesy of AMERICAN HONDA MOTOR CO., INC.

USA

Fig 3: Checking Continuity Between Terminal 6 Of Climate Control Unit Connector A (20P) & Body Ground - USA
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Check for loose wires or poor connections at climate control unit connector A (20P). 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 wires between the climate control unit and body ground. If the wire is OK, check for poor ground at G503 and/or G601.