[CREWZIN]

Chrysler has a TSB (Technical Service Bulletin) for your problem:

NUMBER: 24-013-05
GROUP: Heating & A/C
DATE: August 4, 2005

SUBJECT:
A/C Cooling Coil Odor

OVERVIEW:
This bulletin involves inspecting for leaves and other foreign material, cleaning, and
treating the cooling coil and housing.

MODELS:

2002 (PG) PT Cruiser (International Markets)
1995 - 2005 (PL) Neon/SX 2.0
2001 - 2006 (PT) PT Cruiser
2001 - 2006 (RG) Chrysler Voyager (International Markets)
2001 - 2006 (RS) Town & Country/Caravan/Voyager
2001 - 2005 (ST) Sebring Coupe/Stratus Coupe

SYMPTOM/CONDITION:

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.

DIAGNOSIS:

If the operator describes, or the technician experiences a musty odor when operating the
A/C system, perform the appropriate Repair Procedure based on the vehicle model.

There's a lot more to this TSB but too long to print it all out in this forum. If your still under warranty take it back to the dealer, if not, it looks to be a couple hours labor:

TIME ALLOWANCE:
Labor Operation No: Description Amount
24-65-02-98 TJ 0.6 Hrs.
AB,CS,DR,DH,D1,KJ,PL 0.7 Hrs.
ST, VA 0.8 Hrs.
JR, LX, PG, PT, RG, RS, WJ, WG, WK, WH, XK 0.9 Hrs.
HB 1.0 Hrs.
AN, DN, LH, ND 1.1 Hrs.

One more thing. Some people have gotten rid of the odor by spraying FABREEZE into all the air ducts. It might take a few treatments.