Think the motor has gone on my sons , he's only ridden it a dozen times !

I disconnected the motor , charged the batteries , then turned the key and checked voltage at the terminals where I dissconnected the motor from ,mi have 38 volts so am I right in saying it has to be a short on the motor ? When I reconnect the motor the lights go out on the throttle and the motor does nothing ? Cheers ,scott

It must be more complicated than this, a dead short on the motor would mean when you apply D.C. power something would get extreamly hot very quickly or put something into protect mode or blow a fuse.

I understand your logic but you need to get someone with a bit of electrical knowledge and a multimeter to check it out, you may simply have a duff battery ie it shows 36v but is not capable of supplying any amps.

Good luck