[chevyhouse]

If you have a one wire hookup to the tranny that means you will only have lockup in overdrive. Wire this to a 12v source through a brake switch that closes when you hit the brakes or splice into the brake light wiring. I don't know what the 3rd wire would be for but the other wire is for a second/third gear lockup option, this is normally used for towing in 3rd as locking the converter greatly reduces heat. This requires interal wiring inside the tranny and a toggle switch to control lockup. The internal wiring is pretty easy but if you don't tow I wouldn't worry about it.
This link should tell you everything you need to know

http://www.bowtieoverdrives.com/cata...SUBCAT&CATID=O