WHAT IS THIS ?????

Push in the knob and see if the side box will stay closed..

 

Looks like an old choke knob.

 

Ejection seat , don't touch it in tunnels or under bridges.

 

It is the fresh air-recirculate air control for your heater/ac system. I owned/drove a 95 9300 for 20 years,same controls.

 

Thanks for this post, i have wondered the same myself.

 

In the old Rrrr model Mack, you kicked your left foot for fresh air, and that top vent helped little. In the reverse position, it did suck the farts out on a cold day, however,,,

 

Don't forget the passenger side vent. What I usually did was have the lower intake and the cab roof facing the rear so it's pulling fresh air (And exhaust, fumes, fuel, and pollution etc) through the cab.

We called that 55 mph air conditoning in summer and a 20 mph wake up device in winter.

 

Get that black gorilla tape. One piece to hold the door shut, one piece perpendicular on each end of that to hold the tape on.
If that doesn't work, use a self tapping screw.
If THAT doesn't work, remove the door and stick a small brown person in there to hold all your shtuff.