Switch on the side of the 3 speed Muncie

[Buggalugs35]

I have searched and searched and cannot for the life of me find what the switch on the side of the Muncie 3 speed is. I thought it was the reverse light switch until I realized it is on the 2-3 shift shaft. I put a new switch in to wire it up and my reverse lights stay on unless I put the truck in 3rd gear.

The little black cable that goes to the switch runs along the bellhousing toward the passenger side of the truck

My granddad owned the truck before and moved the column shift to the floor and just painted the reverse lights red and hooked them to the brakes. I have been rewiring the truck and wanted to make them right.

It's a 71 350, any help would be much appreciated. My Chilton shows the switch but not what it goes too.

http://i50.photobucket.com/albums/f3...pste9owl4q.jpg

http://i50.photobucket.com/albums/f3...psn0ozqpdh.jpg

http://i50.photobucket.com/albums/f3...psdfphmn3q.jpg