HVAC Control Power and Ground Circuit Troubleshooting
|1.||Check the No. 36 (10 A) fuse in the under-dash fuse/ relay box.|
Is the fuse OK?
YES - Go to 2.
NO - Replace the fuse, and recheck.n
|2.||Disconnect the HVAC control unit 24P connector.|
|3.||Turn the ignition switch ON (II).|
|4.||Measure the voltage between the HVAC control unit 24P connector terminal No. 23 and body ground.|
Is there battery voltage?
YES - Go to 5.
NO - Repair open in the wire between the No. 36 fuse in the under-dash fuse/relay box and the HVAC control unit.n
|5.||Turn the ignition switch OFF.|
|6.||Check for continuity between the HVAC control unit 24P connector terminal No. 21 and body ground.|
Is there continuity?
YES - Check for loose wires or poor connections at the HVAC control unit 24P connector. If the connections are good, substitute a known-good HVAC control unit, and recheck. If the symptom/indication is still present, substitute a known-good HVAC control unit, and recheck.n
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 G504.n