| • | Debris is present in the HVAC module assembly. | 
| • | Microbial growth on the evaporator core. | 
| • | 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. |