Hello, I have a 1942 chevrolet fire engine from the war era and i have not had any problems with this truck until now with my headlights. I am having a problem with the headlights turning off after about 15-20 mins of running. I am assuming that the circuit breaker in the switch is overloading and tripping it out. All headlight wiring is original with the truck, the generator was changed over and it has a leece neville electrical system 6v installed for higher amperage. All in cab original switches are intact and appear to be in good running order. I am looking for ideas on how to check for a short somewhere as it's headlights only. parking lamps are on another circuit. All wiring doesnt appear to have any burn marks or frays under the hood. let me know thanx.