Recently bought an outside frame 0n30 consolidation and when I unplugged the two prong plug from beneath the cab the female portion pulled off the circuit board.  It seemed the other two prong plug on the board lead to the headlight so I unplugged that from the board and hard wired it to the one from the tender and the loco would not run.  It now seems the wires at the headlight are dead.  Any suggestions on how to troubleshoot and repair......Also...how can I check to be sure that the headlight is not burned out?