Heater Control Power and Ground Circuit Troubleshooting

Heater Control Power and Ground Circuit Troubleshooting

1. Check the No. 14 (10 A) fuse in the under-dash fuse/relay box.

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. 14 (10 A) fuse circuit.


2. Disconnect the heater control panel 30P connector.

3. Turn the ignition switch to ON (II).

4. Measure the voltage between terminal No. 3 of the heater control panel 30P connector and body ground.

Is there battery voltage?
YES - Go to step 5.

NO - Repair open in the wire between the No. 14 (10 A) fuse in the under-dash fuse/relay box and the heater control panel.






5. Turn the ignition switch to LOCK (0).

6. Check for continuity between terminal No. 4 of the heater control panel 30P connector and body ground.

Is there continuity?
YES - Check for loose wires or poor connections at the heater control panel 30P connector. If the connections are good, substitute a known-good heater control panel, and recheck. If the symptom/indication goes away, replace the original heater control panel.

NO - Check for an open in the wire between the heater control panel and body ground. If the wire is OK, check for poor body ground at G501. Dashboard Wire Harness A (Left Branch) and Tweeter Subharness Connector and Harness Locations