Headlights fuse blows after revving the engine

Ok so I have read thru this site and the closest issue I have seen is when lights won’t come on after starting. So to frame this I lost power to my headlights randomly a few weeks ago. Replaced the fuse which blew as soon as I turned the ignition switch. After some research I swapped the fan and low power relays this brings me to a state where the lights cut on and stay on without blowing I got a replacement relay for fan also. However, when I start the bike the lights will stay on for five seconds then blow. I’ve tried it with low beams only and the high beams on they blow the 15amp fuse shortly after starting and revving bike any ideas? What to test? Would the dimmer switch be an issue or is it the voltage regulator (rectifier)

Put a meter in line and check output voltage would be a starting point.

1) Check p/n of relays. May be internally different.
2) vibration of engine could reintroduce possible short where wiring has frayed and is touching frame.

Voltmeter definately required for troubleshooting. Strange problem.

Sometimes you need to do more than just ride

Will be purchasing a multimeter to test the resistance across the wires. I am suspecting my rectifier May be faulty since it only blows once I rev the bike will start their but also check dimmer switch