HVAC Control Power And Ground Circuit Troubleshooting

HVAC

HVAC Control Power and Ground Circuit Troubleshooting

HVAC Control Power and Ground Circuit Troubleshooting

NOTE: Do this troubleshooting procedure only if sent here by symptom troubleshooting.

1. Fuse check:

-1. Check the following fuse.






Is the fuse OK?
-YES- Go to step 2.
-NO- Replace the fuse, and recheck. If the fuse blows again, check for a short in the No. B22 (7.5 A) fuse circuit.

2. Open wire check (IG2 A/C line):

-1. Disconnect the following connector.






-2. Turn the ignition switch to ON (II).

-3. Measure the voltage between test points 1 and 2.










Is there battery voltage?
-YES- The IG2 A/C wire is OK. Go to step 3.
-NO- Repair an open in the wire between the No. B22 (7.5 A) fuse in the under-dash fuse/relay box and the HVAC control unit.

3. Open wire check (GND line):

-1. Turn the ignition switch to LOCK (0).

-2. Check for continuity between test points 1 and 2.










Is there continuity?
-YES- The GND wire is OK. Replace the HVAC control unit HVAC Control Unit Removal And Installation.
-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 G502.