Using documented fixes from the and owner forums:
If you are installing the Px-3994a-a yourself, keep these critical safety points in mind: Clarion | Product Manuals Download Service Clarion Px-3994a-a Manual
: If the exact "Px-3994a-a" model doesn't appear immediately, look for the base model series (often printed on the faceplate). Using documented fixes from the and owner forums: