Report Heater Air Filter Location? in 1965-83 Avanti Posted Monday at 08:05 PM On my 81, the heater fan makes noise but there is almost zero airflow, even on High. So figured I would start with the basics and look for clogged ducts. The workshop manual for the Studes shows an air filter on the passenger side, but I see no such thing anywhere. Where on the later Avanti's with AC is that intake and filter? Or does it not exist? On a general note, is there a way to troubleshoot the fan and ducts without pulling apart the entire heater core assembly? And is there a good step by step on doing that somewhere? Thanks in advance for any help.