Civic L4-1668cc 1.7L SOHC MFI (2003)
Control Assembly: Component Tests and General Diagnostics
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.