HVAC Control Power and Ground Circuit Troubleshooting

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2017 Honda Odyssey, 2016 Honda Odyssey, 2015 Honda Odyssey, 2014 Honda Odyssey, and 2013 Honda Odyssey. However, it is still accessible from the selected car via links, so may be relevant.

Check the No. C26 (7.5 A) fuse in the driver's under-dash fuse/relay box.
Is the fuse OK?

YES -Go to step 2.

NO -Replace the fuse, and recheck. If the fuse blow again, check for a short in the No. C26 (7.5 A) fuse circuit.
Disconnect the HVAC control unit 28P connector.
Turn the ignition switch to ON (II).
Measure the voltage between HVAC control unit 28P connector terminal No. 1 and body ground.

Fig 1: Measuring Voltage Between HVAC Control Unit 28P Connector Terminal No. 1 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Go to step 5.

NO -Repair an open in the wire between the No. C26 (7.5 A) fuse in the driver's under-dash fuse/relay box and the HVAC control unit.
Check for continuity between HVAC control unit 28P connector terminal No. 12 and body ground.

Fig 2: Checking Continuity Between HVAC Control Unit 28P Connector Terminal No. 12 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Check for loose wires or poor connections at the HVAC control unit 28P connector. If the connections are good, substitute a known-good HVAC control unit (see HVAC CONTROL UNIT REMOVAL/INSTALLATION ), and recheck.

NO -Check for an open in the wire between the HVAC control unit and body ground. If the wire is OK, check for poor ground at G403 (see CENTER LOWER CONSOLE SUBHARNESS (AC) ).