It mounted directly to the package tray, with a grille which has fins in two directions. Same as Camaro at the rear but with a Pontiac rocker-style switch common to 69-72 Pontiacs. I believe the shelf-mount defogger was common to much of the GM line in those years, but not too many were sold since they were so pitiful in getting the job done. I know I've seen them in other cars such as Cutlass, LeMans, Chevelle. I added a grid rear window to a Cutlass I owned (72 model), and while searching the boneyards I got control panels for both the blower and the grid, likely from 70 or 71 cars - but that was 22 years ago! The ducted unit was I believe for convertibles - a very few had them installed.
Glenn Uettwiller -
[email protected]
http://firstgenfirebird.org/show/closeup.mv?CarID=209
http://firstgenfirebird.org/show/closeup.mv?CarID=210
"I'm an atheist before my first cup of coffee." - Chuck Colson