belt that squeals

i have noticed some squealing like a belt slipping when my heater is engaged. the squealing only happens when shifting from lower gears and downshifting from 3rd to 2nd. this noise only happens when the heater is on (levers pulled up). the belts are new and were installed by the local porsche dealer. does anyone have any ideas to rid this noise? thanks in advance.

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Sounds like your alternator belt is slipping. When you turn your heater on, it draws power from the battery which in turn is charged by the alternator. May have to readjust it.

Steve

thanks for the info. i checked my owners manual and it says that even new belts have to be checked and adjusted even after the are installed. i'll check it out, thanks again.