PTC Heater Circuit Troubleshooting
  1. Measure the voltage between the heater control unit 32P connector terminal No. 19 and body ground.
Is there battery voltage?
YES -
Go to Step 13 .
NO -
Repair open in the wire between the under-hood fuse/relay box and the heater control unit. If the wire is OK, replace the under-hood fuse/relay box. ■
  1. Substitute a known-good heater control unit, and recheck.
Is the symptom goes away?
YES -
Replace the original heater control unit .■
NO -
Replace the PTC heater core.■