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A/C evaporator odor service



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 evaporator core. During normal A/C system operation, condensation forms in and around the A/C evaporator. When airborne pollutants mix with this condensation, bacteria and fungi growth begins and odor results.



NOTE: As of August 2005 this procedure has been updated via  TSB # 24-013-05



Repair procedure

Parts required:  Mopar 04897625AA Cleaner, Aerosol Evaporator


NOTE: FOLLOW ALL CAUTIONS AND WARNING SUPPLIED WITH THE AEROSOL EVAPORATOR CLEANER; KEEP OUT OF REACH OF CHILDREN; AVOID CONTACT WITH SKIN OR EYES; WEAR SKIN AND EYE PROTECTION, IF SKIN OR EYE CONTACT OCCURS, WASH SKIN OR FLUSH EYES WITH GENEROUS AMOUNTS OF WATER; AVOID BREATHING VAPORS.


1. Inspect the evaporator and HVAC housing for leaves or other foreign material that may be blocking the air flow through the evaporator. If the build up is excessive, replacement of the evaporator may be required.

2. With the parking brake applied and the transmission in Park, start the engine and let idle. Put the temperature control to full hot, blower speed to HIGH, select the PANEL and RE-CIRCULATE modes. Open all windows about 13mm ( in.). Disable the A/C compressor clutch by disconnecting its wiring connector or the wiring connector to the A/C pressure switch.


NOTE: THIS PROCEDURE HEATS THE EVAPORATOR AND CAUSES MOISTURE TO EVAPORATE FASTER. THE SLIGHTLY OPEN WINDOWS ALLOW MOISTURE TO ESCAPE THE VEHICLE WITHOUT LOOSING MUCH HEAT. SOMETIMES, YOU MAY SEE A "FOG" CLOUDING THE WINDOWS. AFTER THIS "FOG" HAS DISAPPEARED CONTINUE TO OPERATE THE HEATER FOR ANOTHER 5 MINUTES. IF THE "FOG" NEVER APPEARED, OPERATE THE HEATER FOR A MINIMUM OF 30 MINUTES.


3. Turn the ignition switch to the OFF position.

4. Gain access to the evaporator cavity to apply the evaporator by removing the blower motor resistor (manual A/C systems) or the blower motor controller (Automatic A/C systems). The resistor (or controller) is mounted to the HVAC housing, under the right side instrument panel and just inboard of the blower motor. It can be accessed without removing any other components.

A. Depress locking tab and unplug the wire harness connector from the blower motor resistor.

B. Depress locking tab and unplug the resistor connector from the blower motor.

C. Remove the 2 screws that secure the blower motor resistor to the HVAC housing.

D. Remove the blower motor resistor from the HVAC housing.


Blower motor resistor removal

Blower motor resistor/controller removal


5. Place a piece of heavy masking tape over the opening in the evaporator housing where the blower resistor or controller was removed, then punch a small hole for the evaporator cleaner tube to be inserted into.

6. Shake evaporator cleaner aerosol can well and insert the application tube in the access hole created in step 4.


NOTE: THE APPLICATION TUBE HAS A BLACK MARK AND A RED MARK ON IT INDICATING HOW FAR THE TUBE SHOULD BE INSERTED INTO THE EVAPORATOR CAVITY. THE BLACK MARK IS FOR GRAND CHEROKEE VEHICLES.


7. Start the engine and let idle. Set the blower motor to HIGH.

8. Put on goggles and dust mask type breathing protection.

9. Spray the entire contents of the evaporator cleaner into the evaporator cavity.


NOTE: A "FOG" MAY BE SEEN ENTERING THE PASSENGER COMPARTMENT WHILE THE EVAPORATOR CLEANER IS BEING SPRAYED. THE EVAPORATOR CLEANER WILL NOT STAIN OR HARM THE VEHICLE INTERIOR, BUT GOGGLES AND BREATHING PROTECTION MUST BE WORN DURING CLEANER APPLICATION. DO NOT BREATH VAPORS!


10. When the can is empty, turn the ignition switch to the OFF position and let the vehicle sit for 20 minutes. This time will allow the cleaner to flow over and coat the evaporator fins and case assembly.

11. Re-install the blower motor resistor in the HVAC housing. The housing is indexed to allow mounting in only one position. Tighten the mounting screws to 2.2 Nm (20 in. lbs.).

12. Open all of the vehicle windows about 13mm ( in.). Start the engine and let idle for a MINIMUM of 30 minutes with the temperature control to full hot, blower speed to HIGH, PANEL and RE-CIRCULATE modes selected. This will dry and cure the evaporator cleaner onto the evaporator coil.

13. Connect the wiring disconnected in step 2 to re-enable the A/C compressor clutch.

14. Verify proper A/C operation.

15. Owners of vehicles that operate in conditions where the air inlet to the hvac housing is subject to foreign material, debris or other airborne contaminates, may want to consider having a mopar accessory cabin air filter kit installed. See Cabin Air Filter.





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