Our 300ex starts up fine and runs great. When you flip the light switch on the on postion it kills the motor. We tool the switch apart and WD-40 it. Then we took the light out and with the switch on or off it runs fine. We had a spare light and tried it with the same results. Any suggestions????????

 

How does the socket, for the bulb look? Crusty or rusty?

 

The socket for the bulb looks fine without any corrosion or rust.

 

whats your email, i'll send you a wiring diagram.. you can make sure everything is in the right order