I've a Cobra 29 CB Radio. It has a 3 pin power plug on the back. The cord supplied with it is a cigerette lighter style, with 3 wires going to the 3 pins on the plug. one side 12v, middle 12v, other side ground. Great. I've another 'universal' cb cord, just 12v on one side, ground on the other. Middle pin is not hooked to anything. The radio operates on either cord. Now, I'm wiring my K5 from scratch, I don't want the cig lighter, I want to wire it directly to my circuit breaker box, and am wondering, what that middle pin is for? Some cords have 12v on it, others have just a blank? The manual just labels the 2 edges 12v and ground. The middle pin isn't labeled. I've been searching and googling, but too much comes with searches like 3pin cb cord, cb wiring diagrm, cb power . Anyone know what that middle pin is supposed to be for?