Heater Control Power And Ground Circuit Troubleshooting

HVAC

Heater Control Power and Ground Circuit Troubleshooting

Heater Control Power and Ground Circuit Troubleshooting

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

1. Fuse check:

Fuse check
-1. Check the following fuse.





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

2. Open wire check (IG2_A/C line):

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 IG2_A/C wire between the under-dash fuse/relay box No. B22 (7.5 A) fuse and the heater control panel.

3. Open wire check (GND line):

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 heater control panel Heater Control Panel Removal and Installation.
-NO- Check for an open in the wire between the heater control panel and body ground. If the wire is OK, check for poor ground at G504.