gio 500 Watt Scooter

Good Day All! I Have A Problem With My Gio 500 watt scooter! It was given to me and i had to do repairs to the wire harness and have a problem with it losing power to the motor but still showing power on the instruments! It seems to lose power after riding for awhile! If I turn off the power button and let it sit for 5 minutes then turn power button on it will go again but for how long is undetermined until it loses power to motor again! I have tried to bypass key switch and power switch but still have the same result! I am hoping someone can give me an idea if it is possibly the wire harness or the controller or maybe a motor problem! Any help or input on this matter would be greatly appreciated! There must be a reason why it loses power to the motor only and will not accellerate when cranking the throttle! Thanx!!!