Troubleshooting Hints - HVAC System - Manual

FRONT TEMPERATURE CONTROLS
1. CHECK the condition of HTR-A/C Fuse 12. If the fuse is open, then LOCATE and REPAIR the cause of overload and REPLACE the fuse.
2. CHECK that Ground G201 is clean and tight.

FRONT VENTILATION MODE CONTROLS
1. CHECK for proper vacuum supply.

REAR AUXILIARY MODE AND TEMPERATURE CONTROLS
1. CHECK the condition of RR HVAC Fuse 24. If the Fuse is open, then LOCATE and REPAIR the cause of the overload and REPLACE the fuse.
2. CHECK that Ground G4OO is clean and tight.

GENERAL
1. Refer to Lighting and Horns for diagnosis of the Instrument Panel Dimming illumination lamp circuits. Lighting and Horns
^ CHECK for a broken (or partially broken) wire inside the insulation which could cause system malfunction but prove GOOD in a continuity/voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a Voltage drop with the system operational (under load).
^ CHECK for proper installation of aftermarket electronic equipment which may affect the integrity of other system (Refer to Troubleshooting Procedures). Diagnostic Aids