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Old 08-29-2009, 10:06 AM   #66
Registered User
Join Date: Apr 2006
Location: Maine
Posts: 297
My Ride: 2002 325i
, I have this same problem. After reading this and other posts, there are several causes for this issue. The HCV failed, low freon, or issues with stepper motor(s) inside the dash. Seems to me if you get nice cold AC with the engine cool, the freon charge should be fine. Once the engine gets up to temp, hot coolant flows to the HCV, which should be closed with AC on if working properly. If it is failed it sticks open causing the mixed heat/cool air issue. What still confuses me is the folks who replace the HCV and still have the problem. Do the stepper motors send signals to the HCV? If a stepper motor is bad, will it cause the HCV to stick open?

Meyle control arms, M3 RTAB's, Bridgstone Potenza RE760
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