Odor from Evaporator or Heat Exchanger?

-- From leak at cooling system of engine or of A/C system heater core.

NOTE:

If the fishy smell gets weaker when the temperature is set to "cold" and stronger when it is set to "warm", then check the heat exchanger for leaks.

-- Due to various contaminants, such as leaves, pine needles, etc. collecting.

NOTE:

Plenum Chamber, Cleaning

-- Due to water that cannot drain out of the plenum chamber.

NOTE:

Plenum Chamber Water Drains, Checking

NOTE:

Odors originating in the heating and A/C unit can mainly be detected in fresh air mode and recirculated air mode.

-- Due to too much condensation water in the heater and A/C unit

NOTE:

Condensation Water Drain, Checking.

-- Due to an old or heavily contaminated dust and pollen filter.

NOTE:

Check the dust and pollen filter.

-- Due to deposits on evaporator fins.

NOTE:

Clean the evaporator using either of the following tools and the cosponsoring spray lance:

Refer to Ultrasound A/C Cleaner for Ultrasound A/C cleaner.