For 1990-2009 cars

Important: A single application of the Air Conditioning Deodorizer, GM P/N 12377951, will remove musty odors from the air conditioning system.

1. Turn the ignition switch to LOCK.
2. Set the parking brake.
3. Make sure the cowl vent grill is clear.
4. Place an auxiliary fan in front of the vehicle.
5. Set the A/C switch to OFF.
6. Set the air mode to VENT.
7. Set the fresh/recirc to FRESH.
8. Set the temperature to full HOT.
9. Start the engine.
10. Set the blower speed to HI for 10 minutes.
11. Remove the I/P compartment. Refer to Instrument Panel Compartment Replacement in Instrument Panel, Gages and Console.
12. Remove the resistor block by removing two screws, then pull from the heater case.
13. Wear safety goggles and latex gloves.
14. Cover the carpet area underneath the HVAC module assembly with shop rags to collect any deodorized liquid that may spill out of the HVAC module assembly.
15. Shake the deodorizer spray can.
16. Install the extension tube into the nozzle of the can.
17. Insert the extension tube into the resistor block hole past the mark on the tube.
18. With the blower still on HI, spray the contents of the Air Conditioning Deodorizer over a 5 minute period with short bursts while varying the direction of the tube.
19. Turn the blower speed OFF.
20. Turn the ignition switch to LOCK.
21. Let the vehicle sit for 5 minutes.
22. After 3-5 minutes, start the engine.
23. Set the blower to the highest speed setting.
24. Operate the blower at this setting for 15-20 minutes to dry the evaporator.
25. Install the I/P compartment. Refer to Instrument Panel Compartment Replacement in Instrument Panel, Gages and Console.