TSB 24-006-06 addresses this problem.
Some vehicle operators may experience a musty odor from the A/C system, primarily at
start up in hot and humid climates. This odor may be the result of microbial growth on the
cooling coil. During normal A/C system operation, condensation forms in and around the
A/C cooling coil. When airborne pollutants mix with this condensation, bacteria and fungi
growth begins and odor results.
If the operator describes, or the technician experiences a musty odor when operating theA/C system, perform the appropriate Repair Procedure based on the vehicle model.