Here's a link to the Power Plug cable that we make. This plugs into the large three pole Amp connector found in most modern tractors.

Fortunately all manufacturers have followed a standard wiring pattern. The pattern is: Pin 1 - Key switched power, Pin 2 - Constant Power and Pin 3 - Ground.

We also make a similar harness with ring terminals that attaches to the terminals on the Deere Power strip. This what I use personally and don't bother with Deere's plugs.

Scroll down the page aways to see the picture.

http://ld-ag.com/tips.htm