Theory of Operation
The A/C mode switch input changes when the switch is pushed down. A stored DTC 33 indicates that the A/C mode switch was stuck in a pushed position for more than 10 minutes, but has since returned to its normal state. An active DTC 33 indicates that the A/C mode switch is stuck in a pushed position. An active DTC 33 will prevent the control from entering diagnostic mode and performing certain diagnostic functions. It will also prevent proper A/C mode switch and status indicator function. For additional information about the A/C Heater Control's on-board diagnostics, refer to Diagnosis and Testing .
- When Monitored:
With the ignition on.
- Set Condition:
If the A/C mode switch stays in a pushed position for more than 10 minutes.
| Possible Causes |
|---|
| OBJECT HOLDING A/C MODE SWITCH IN A PUSHED POSITION |
| SUBSTANCE CAUSING A/C MODE SWITCH TO GET STUCK IN A PUSHED POSITION |
| (C850) BLOWER SWITCH POSITION SIGNAL CIRCUIT SHORTED TO VOLTAGE |
| (C850) BLOWER SWITCH POSITION SIGNAL CIRCUIT SHORTED TO (Z908) GROUND CIRCUIT |
| (C850) BLOWER SWITCH POSITION SIGNAL CIRCUIT SHORTED TO (Z909) GROUND CIRCUIT |
| (C850) BLOWER SWITCH POSITION SIGNAL CIRCUIT SHORTED TO GROUND |
| (C850) BLOWER SWITCH POSITION SIGNAL CIRCUIT OPEN |
| A/C STATUS INDICATOR INOPERATIVE |
| A/C HEATER CONTROL |