2008 Chevrolet Impala - Clicks

when using AC and changing fan speed, or distribution from floor dash to just dash a rapid clicking sound begins and continues for several minutes.I thought the fan might be striking something. I removed the fan and tried the AC again. Clicking again started after changing settings, with fan out I reached back under where sound was coming from and touched something very hot almost burning myself. Put it all back together and still have the same problem. The clicking sound is fairly loud.and only happens on AC s

It is the blend door actuator.