Proberly a bad voltage regular,had that problem before.try putting on the lights then start car or start the car ten put on the lights.

Yes, both the light and the voltage are controlled by the VR. I'd say it is bad.

Normal charge voltage should be 13.8 to 14.8 volts, but if the battery is low it could possibly go that high. Another thing to look at is if the electrical connectors are not clean, as in bright and shinny, this could cause high resistance in the circuit and cause the regulator to raise the voltage to overcome it.
Personally I would start by cleaning all the electrical connections.

So i have bought a new external voltage regulator for my 120y and replaced the brushes in my alternator

the problem i am having is that when the ignition is turned on the charge light does not turn on

then when you start the car the charge light turns on a will keep getting brighter as the rpm increase my multimeter shows close to 16volts

and when i connect the external regulator the engine seems to sound loaded up and when you disconnect it the rpm goes up abit

this makes me think its a voltage regulator problem but its brand new

any ideas?

Thanks