Hook it up like any other siren, with the heavy wire going to positive, and grounding the frame. The main difference is that you have to apply power to the positive wire of the brake to release the brake, where as on the Federal sirens, you apply power to the brake to engage the brake. The reason for this is that the siren will start to howl as you go down the road, without the siren in use, if the brake isn't engaged. The brake is always engaged, until you apply power to it. I have posted the Siren wiring diagram that is on the B&M Siren website. There is also a maintenance manual on the website.