Operation CHARM: Car repair manuals for everyone.

Heater Control Power and Ground Circuits Troubleshooting

Heater Control Power and Ground Circuits Troubleshooting

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

Is the fuse OK?

YES - Go to step2.

NO - Replace the fuse, and recheck.

2. Disconnect heater control panel connector A (14P).
3. Turn the ignition switch ON (II).




4. Measure the voltage between the No.14 terminal of heater control panel connector A (14P) and body ground.

Is there battery voltage?

YES - Go to step 5.

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

5. Turn the ignition switch OFF.




6. Check for continuity between the No.13 terminal of heater control panel connector A (14P) and body ground.

Is there continuity?

YES - Check for loose wires or poor connections at heater control panel connector A (14P). 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 ground at G502.