Eliminate Air Conditioning Odors
Unpleasant odors may sometimes emanate from your air conditioning system. These odors are usually the result of fungus growing on the surface of the air-conditioning evaporator core. The humid, warm atmosphere there is great for fungus growth. Although it is difficult to access the evaporator core on many vehicles, it can be done. You can perform this service in your home garage, but you will need a powerful disinfectant; household deodorizers or germ-killers will not do the job.
Note: these are general instructions. Consult a repair manual written specifically for your truck, car, SUV or van for the exact procedure.
You can purchase an aerosol disinfectant at an auto supply store. Remember that the most expensive treatments are the most effective. Be sure the disinfectant has a long spray tube connector.
Start your engine and run the heating system in recirculation mode for about 10 minutes with the temperature on HIGH. The high temperature dries out the system. You do not want the air conditioning system to operate at this time, so disconnect the a/c compressor by removing the wire connector at the unit.
Point the nozzle of the long spray tube through the interior ventilation filter chamber and allow it to protrude inside the evaporator housing. Spray according to the manufacturer's instructions. Aim the spray down, up and sideways to try to cover the entire surface of the evaporator. Follow the manufacturer's instructions, too, for how much to spray and the length of wait time between applications.
To prevent the mildew from growing back after you have cleaned and disinfected the evaporator, the best thing is to make sure the evaporator drain tube is clear. Locate the drain tube (refer to your vehicle's repair manual). Remove the drain tube, clean it and keep it clean.
Your air conditioning system should now provide you with cool, odor-free air.