On a 2002 E-150 CONVERSION VAN has anybody else had to replace what appears to be some sort of re-circulation box/motor? that is located in the left rear behind the bench seat mounted to the side panel with vents on the bottom of it? What would you call that thing in case I have to try and find one? Im worried that it may not be a dealer item and only a conversion installer item which might make it hard to replace. Any help would be appreciated. Thank you.