Zero Turn Mowers

I have a husqvarna cz3815 zero turn. I can start it with the key on by jumping the starter solenoid and shut it off with the key hit cant physically start it with the key alone as I should be able to. When I get it started it runs great until I try to move my steer arms or engage the deck. It acts like my parking brake is still engaged even though it isnt. I've replaced the ignition switch, starter solenoid, brake relay, start relay and parking brake switch. What did I do?