I don't have a picture of the only style that was used on the TF trucks handy, but will get one tomorrow - sounds like you have an aftermarket unit, or one adapted from the 60's, when they started using electrical switches rather than mechanical, especially with having to change the arms ... got any pics of these units?

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