Piecing this thread together with what you said in the other thread... you'll need the Whelen Control Point to make the lightbar work. You have a single color Whelen Legacy WeCan lightbar. The options are almost endless with programming, and you'll only need low current switches to control the features you choose to program. We can help you through the process.
Basically, the Control Point converts a low current signal input to a digital signal that communicates with the board inside the lightbar.