I'm having an issue with the headlight on my Coolster 110cc quad. When I turn the key on the taillight comes on but when I turn on the switch for the headlight, nothing happens. There are three wires that go to the connector that connects to the headlight. A white, a blue and a green wires. I traced the white wire to the voltage regulator. I traced the green wire to the engine ground and the blue with goe's to the switch and to another connector that has nothing hooked to it. I believe the issue is either the switch or that connector that has nothing connected to in at the front of the quad. I made a video of this and tried to attach it but it didn't seem to be working. It's a MOV file so not sure why it's not working. Thanks so much for your help!

 

Have you tried switching the light on with the engine running, unlikely if it has the tail light worked from the battery, but running the "live" from the regulator rather indicates a direct power from alternator headlight. Also possible it is just a blown bulb, have you checked?

 

I have tried the headlight with the engine running and it didn't work and also checked the bulbs in the headlight and both are good. I think I have it narrowed down to either a bad switch on the handlebar or something related to the unused connector at the front of the quad.