What year, make model and engine size? A lot of times if the heater control valve does not close all the way or the flap is deteriorated it will let hot water continue to come in the heater core. When this happens and you cut the a/c on it tries to blend the two which results into warm air coming out when a/c is on.
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What year, make model and engine size? A lot of times if the heater control valve does not close all the way or the flap is deteriorated it will let hot water continue to come in the heater core. When this happens and you cut the a/c on it tries to blend the two which results into warm air coming out when a/c is on.