Heater Control Power and Ground Circuits Troubleshooting
Heater Control Power and Ground Circuits Troubleshooting1. Check the No. 16 (30 A) fuse in the under-hood fuse/relay box, and the No. 16 (7.5 A) and No. 18 (7.5 A) fuses in the under-dash fuse/relay box.
Are the fuses OK?
YES - Go to step 2.
NO - Replace the fuse(s), and recheck.
2. Disconnect heater control panel connector A (12P).
3. Turn the ignition switch ON (II).
4. Measure the voltage between the No. 2 terminal of heater control panel connector A (12P) and body ground.
Is there battery voltage?
YES - Go to step 5.
NO - Repair open in the wire between the No. 16 fuse in the under-dash fuse/relay box and the heater control panel.
5. Turn the ignition switch OFF.
6. Measure the voltage between the No. 3 terminal of heater control panel connector A (12P) and body ground.
Is there battery voltage?
YES - Go to step 7.
NO - Repair open in the wire between the No. 18 fuse in the under-dash fuse/relay box and the heater control panel.
7. Check for continuity between the No. 10 terminal of heater control panel connector A (12P) and body ground.
Is there continuity?
YES - Check for loose wires or poor connections at heater control panel connector A (12P). 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 G404.