Odor Diagnosis

Some vehicles may experience odors emitted from the air conditioning system primarily at start up in hot, humid climates. This odor may be the result of debris in the evaporator module case and/or microbial growth on the evaporator core. To eliminate this condition, Goodwrench Air Conditioning System Deodorizer (GM P/N 12377951) and the following procedure should be used.

Important:

This procedure will eliminate debris or microbial growth which can cause odors but will not keep such debris or microbes present in the environment from causing a recurrence of the problem. However, installation of a Delayed Blower Control Module (GM P/N 12370470) is recommended to prevent the odor from returning.

1. Make sure that the plenum duct that draws air from the outside is clear of all debris.
2. Disable the A/C compressor clutch operation by disconnecting the clutch coil electrical connector.
3. Reference Service Bulletin (#53-12-12) for location template and method of injecting spray onto the evaporator. If the bulletin is not available, locate an area between the blower motor and evaporator, downstream of the fan and drill 3.175 mm (1(8 inch) hole where it will not interfere with any operating components.
4. Set blower control to "HIGH" and temperature control to "MAX" position.
5. Run engine for ten minutes to dry evaporator.

CAUTION: Use approved safety glasses and gloves to reduce the chance personal Injury.

6. Shake can well and insert extension tube into the nozzle of spray can.
7. Insert extension tube into hole of HVAC module past the mark on the tube.

Important:

Spray can must be held in upright position to ensure the entire contents is dispensed.

8. Dispense entire contents of can in varying directions over 2-3 minute period.
9. Turn engine off and let sit for five minutes.
10. Seal the access hole using RTV gasket compound.
11. Run engine for twenty minutes with blower control set to "HIGH" to dry HVAC module.
12. Connect the A/C compressor clutch coil electrical connector.