Chris - not sure on factory original, but heater switches are normally variable [rheostat] not toggles - this is what our sponser offers:
[img]http://www.americanclassic.com/images/EL118.GIF[/img]
difference in recirc and "fresh air" heaters is a cable control for opening a vent for outside air

Bill


Moved over to the Passing Lane

"When we tug a single thing in nature we find it attached to the rest of the world" John Muir
"When we tug a single thing on an old truck, we find it falls off" me
Some TF series details & TF heater pics & Rust-a-holics Unanimous parking lot