For 1990-2009 cars

Important: Using a Scan tool check DTCs P0532, P0533 and P0530. If present, diagnose these DTCs first.

SYMPTOM | PROCEDURE
--- | ---
All blower motor speeds inoperative | Chart 1
Blower motor operates in HI speed anytime blower switch is activated | Chart 2
Blower motor operates in HI, but not in one or more of the other speeds | Chart 3
Blower motor operates in all modes except HIGH | Chart 4
No outside or inside air circulation - blower motor functions | Chart 5
A/C compressor does not operate | Chart 6
Mode doors motor not functioning | Chart 7
A/C compressor operates all the time | Chart 8
A/C or recirc switch indicator lamps do not light | Chart 9
Only HVAC lights do not illuminate or dim with I/P dimmer (all the lights for the other systems function correctly) |

• | Check for voltage between HVAC Control Head terminal B4 (GRA, circuit 8) and a known good ground with park lamps on. If no voltage is present, repair circuit 8.

• | If voltage is present at terminal B4 (circuit 8) and all other HVAC functions operate, faulty bulbs or control head.

• | Check HVAC dimmer operation.