HVAC Recirculation Mode and Compressor-On Operation - kw AC bind defogger dim defrost headlamp intermittent light inoperative LED lamp mode moisture operation poor rear

When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

Incomplete explanation in owners manual or eSI for HVAC recirculation mode and compressor-on.

There are a number of operational characteristics that may not be apparent to a technician regarding the way the new for 2004 HVAC system works. Listed below are some scenarios that may explain normal operation:

When the 'recirc.' (recirculation) mode is activated and the LED is lit on the button, the 'recirc.' door closes and is allowed in all modes except floor and defrost. It was decided to leave the light on if the customer first selected 'recirc' while in another mode.

The 'recirc.' button LED remains lit but the door will go to outside air mode, but the outside air LED will not light.

When switching modes back to the vent or bi-level positions the 'recirc' light will still be lit and the door will again go back to its closed position as originally selected.

Additionally, when the key is cycled off and then back on again, the outside air position comes on as a default, 'recirc.' cannot be expected to resume upon restart without first selecting it.

In floor mode, the AC compressor is automatically activated and engaged including the floor/defrost mode and any position with the selector knob turned to the right of the floor mode setting even without the A/C button selected. Otherwise, in vent and bi-level, the A/C does not engage unless the A/C button is pushed.

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Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.

(04 Chevrolet Impala)

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