GM Service Manual Online
For 1990-2009 cars only

Eliminating Air Conditioning Odour

  1. Odours may be emitted from the air conditioning system primarily at start up in hot, humid climates. The following conditions may cause the odour:
  2. • Debris is present in the HVAC module assembly.
    • Microbial growth on the evaporator core.
  3. When the blower motor fan is turned on, the microbial growth may release an unpleasant musty odour into the passenger compartment. To remove odours of this type, the microbial growth must be addressed. Perform the following procedure:
  4. • Remove evaporator core. Refer to Air Conditioning Evaporator Core Replacement.
    • Clean evaporator core with a solution of 40% vinegar and 60% water.
    • Refit evaporator core. Refer to Air Conditioning Evaporator Core Replacement.