what would make brake lights stay on even when truck is shut off

Faulty stop light switch or out of adjustment, located at brake pedal arm.

theres a arm by the peddel thats not connected how do i connect it up

If its the switch, its small and has an eye that fits over a peg on the brake arm, then a retaining clip goes on to hold it in place. For a picture, go to http://www.rockauto.com and look up your truck.