SiPPMSH nailed it. Back in the "olden days," all three of the terminals came prewired from the factory; one 'keyed hot' (the one you have), the middle terminal was a ground point, and the other terminal was 'hot all the time.' For the 900, you can buy a Polaris harness that makes the other two terminals usable (it's included with some Polaris options such as the winch and the radio, and ??)--I don't know if one is available for the mid-sizes or not, I would assume there is. Never-the-less, you can make your own harness very easily by running a cable off your battery's + and - lugs to the terminal. Just make sure you size the cables to handle whatever load you expect you would be attaching to those terminals. Since those two terminals are not wired to anything (unless you have the afore mentioned options) you could really use them for whatever you want. BTW, the one you have now (with orange wire on it) is protected by a 20 amp fuse and also feeds your aux plugs (cigarette lighters) in your cab.