Electric brakes, or hydraulic surge brakes? A 3 axle trailer capable of hauling a backhoe is probably pushing the envelope for electrics unless you're planning to run brakes on more than one axle. Modern electric controllers don't require any hydraulic connections like the older ones did- - - -there's a pendulum built into the controller that energizes the electric brakes according to how quickly the tow vehicle is being braked. Just follow the printed instructions that come with the controller. The controller needs to be mounted in a position where it can be leveled- - - -they don't work well, or sometimes at all if they're not level so the pendulum can swing properly.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!