'05 Dodge Ram 2500 -Backup Wire

I am trying to finsih up the install of my N1.

and I hopefully thanx to the vss/tach info page, can now find the VSS wire, but I also am having a heck of a time finding the reverse wire

I have a 2005 Dodge Ram 2500 Quad Cab, 5.7

Any help would be greatly appreciated.

Taz

Also, forgot to put this above, BUT also, can someone tell me what type of Reading i should be getting from the VSS wire..

I belelive the TACH wire, is a varying AC voltage (between 2-6 volts AC), but i would like to find out what the VSS wire is, so i can make sure i have the right line.