The air conditioning system may emit odors at start up. This condition primarily occurs in hot, humid climates. Debris in the heater/evaporator case or mold on the evaporator core may cause odor.

Caution: Procedure should only be performed on a cold vehicle to prevent the disinfectant from coming in contact with hot engine components. Disinfectant can cause substantial but temporary eye injury. Do not get in eyes or clothing. Wash thoroughly with soap and water after handling.

1. Ensure that the plenum that draws air from the outside is clear of all debris.
2. Disable the A/C compressor clutch operation by disconnecting the clutch coil.
3. In order to dry the evaporator core, complete the following steps:

3.1.	Turn the ignition switch to the ON position.

3.2.	Operate the blower motor for a 10 minute period under the following conditions:

•	Set blower speed on the high position.

•	Set the recirculation mode.

•	Set the temperature control on maximum heat.

4. Locate an area in the air condition duct downstream of the blower motor fan, between the blower motor and the evaporator core.
5. Drill a 3 mm (1/8 in) hole in a location that does not interfere with the blower motor, the evaporator, or any operating part in the system.
6. Using safety goggles and latex gloves, insert the extension tube of the deodorizer GM P/N 12377951 into the hole past the mark on the tube.

•	Spray the area in short bursts.

•	Dispense the contents of the can over a period of 2-3 minutes.

•	Vary the direction of the spray into the duct.

7. Turn the ignition switch to the OFF position.

Allow the vehicle to sit for a period of 3-5 minutes.

8. Seal the hole in the duct with a body sealer or with a room temperature vulcanizing gasket compound.
9. Turn the ignition to the START position.
10. With the fan on the high speed, idle the engine for a period of 15-20 minutes in order to dry the sealer or the compound.
11. Reconnect the air conditioning compressor clutch coil.
12. Verify the operation of the air conditioning system.