Chrysler Repair: AC/Heater squeeling sound, high humidity, rain water

Question
My AC/Heater...sometimes makes a loud squeelling sound for about a minute or so and then stops....may start again later....I turn the ac/heat off and the squeel stops...what is it...a belt?......it is even worse after a rain or I wash the car or run through a puddle..etc..

Answer
Hi Edward,
If it is a sound that is coming from the engine compartment then I would believe that the belt that is driving the ac compressor is slipping when you hear the sound and similarly when water or high humidity is in the vicinity it will slip more easily/likely. Using the heater only (not the defroster) should not cause the sound if that compressor were the cause.
You didn't mention which engine you have so I can't tell you how to adjust/inpect the belt but that would be the corrective action. It could be the belt is tight enough but is warn/glazed such that it is too "slippery" on it surface.
If it sounds like it is in the vehicle then I would suspect the blower fan motor or the fan rotor is touching the housing. The loudness with rain/car wash in that case would be because of rain/water getting into the intake for the system and getting into the blower housing. That can be reduced by putting the system on "re-circ" when you turn it off.
Those are my best ideas.
Roland