Just curious, what is that box that is on the passenger side directly under the dash pad, sitting vertically in the void between the trim and the ducting?

Well it depends on the year, make, & model of car you are talking about. It could one of several things; the ECM readily comes to mind, the VSS buffer box. or the DERM (Diagnostic Energy Reserve Module) for the air bags. Got any pictures of it. If it is a 1985 model camaro it could be the MAF burn-off relay but that is mounted to the ECM.

https://www.thirdgen.org/techbb2/sho...hreadid=322843

The above thread seems to have answered my question... Cruise control module? 1989 2.8L Firebird.