2008 dyna lowrider run switch will not activate,

"The two small hydo lines entering it seem to be loose and spring loaded turn screw is also loose"

I think you're referring to the two throttle cables and the throttle lock screw on the bottom of the throttle mechanism.

The "run/stop" switch is located inside the switch housing on the throttle side. It has three wires running to it. If the switch does not work, it may be defective.

To replace the switch, you must remove the two bolt that hold the switch halves together. Carefully seperate the two halves. the "Run/Stop" switch is in the front half of the switch housing. The switch is held in by a couple of small screws. Remove the switch and unsolder the wires taking note of which wire goes where. Resolder the wires to a new switch and install the switch in the housing. Reassemble housing keeping it positioned up firmly against the front brake master cylinder. Check the throttle for proper operation prior to starting the engine.