Blower and Heater Controls Do Not Work (Without A/C)

Blower and heater controls do not work

Diagnostic Procedure:

1. Probable cause: Control unit malfunction or faulty power or ground circuits

2. Check for DTCs using the HDS or the self-diagnostic function How To Troubleshoot the Heating System (Without A/C)

3. Do the heater control power and ground circuit troubleshooting Heater Control Power and Ground Circuit Troubleshooting (Without A/C)

Also check for:

- Blown fuses No. 20 (7.5 A) or No. 25 (7.5 A) in the under-dash fuse/relay box
- Blown fuse No. 54 (30 A) in the main under-hood fuse/relay box
- Faulty blower motor relay
- Poor body ground at G402
- Poor or loose connections at the terminals