My manual states this about the Off button on the HEAT/AC...

"In this setting, the fresh air supply to the interior of the car is shut off,
(to prevent enterence of odors, ie: while driving through tunnels etc. or to prevent the enterence of water from automatic car wash). Use this setting only temporarily while driving."

Is this simply so I don't suffocate?

Why can't I drive around without heat blowing on me in the summer?
(besides that my AC dosent work)

Will leaving it off damage something?

__________________
OBK #32
1985 300D Turbo (15 gal Greasecar kit installed)
(258,900+mi.) Thanks- Tachometer Fixed. Middle Vents Fixed. Transmission- 1000% better shifting.
Vac leaks- Fixed, Brakes replaced, Steering Box replaced, .... Information Rules.