I have a 1992 Camry i4 LE that as long the air is turned on is constantly blowing through the defroster regardless of the setting on the air controller knob. Any ideas as to what could be wrong?

So I found out the problem is one of the dampener flaps in the vent system. The plastic arm connecting it to the servomotor mechanism is broken. Specifically it is the little metal bar connecting to central vent dampener I believe. Any thoughts as to an easy fix or where I could get a replacement?