Odors may be emitted from the air conditioning system at startup in hot climates. Debris in the heater/evaporator case or growth of mold on the evaporator core may cause this odor. A service kit is available through GMSPO.

A single application of this deodorizer, GM P/N 12377951, will remove the odor from the air conditioning system. However, to prevent the odor from returning, enabling the blower control function with the scan tool is recommended. Refer to Afterblow Enabling .

1. Clear all the debris from the plenum that draws air from the outside.
2. Disconnect the clutch coil. This will disable the A/C compressor clutch operation.
3. Dry the evaporator core by turning the engine on. In addition, run the blower motor on high and in a recirculating mode, with the temperature control on maximum heat for 10 minutes.
4. Remove the passenger compartment air filters. Refer to Passenger Compartment Air Filter Replacement .

Important: Use safety goggles and latex gloves for the following step.

5. Keep the blower motor on high and insert the extension tube of the deodorizer, GM P/N 12377951, into the filter access hole past the mark on the tube.
6. Spray the area with short bursts. Dispense the contents of the can over a 2-3 minute period. Vary the direction of the spray into the duct.
7. Turn the engine off.
8. Let the engine sit for 3-5 minutes.
9. Start the engine and run the fan on high for 15-20 minutes to dry.
10. Install the passenger compartment air filters. Refer to Passenger Compartment Air Filter Replacement .
11. Reconnect the air conditioning compressor clutch coil and verify the operation.