key ignition switch problem
 

this is on my sons mini dune buggy. It has a 3 wire turn key start ignition switch the the po has never got working. I have switched out the starter solenoid with a known working one and i still get the same results. I turn the key to crank and nothing, so i leave the key in the run position and jump the solenoid and it starts. I woould like to get it to work with the key as its intended. Any suggestions? The key switch i'm assuming works as the headlights and gear selection lights as well as all other things work once the key is turned on, just not the start function.

One wire goes from the switch goes to the solenoid to power it up in the start position. If there isn't power at the small solenoid wire,could be a switch or wire problem. If the solenoid wire has power then could be a ground problem if the frame is ground.