The green light on the headlight of my 1977 t140v stays on and flashes with turn indicators. Is this normal?
Nope. The little Green light should show high beam. The little Orange light should flash with the indicators. The little Red light comes on when you turn on the ignition and goes out when you have oil pressure. If the little red light comes on while running then you have an oil pressure issue (you need to stop the engine immediately and run away). I reckon you have a wiring mix up/grounding in the headlamp shell. That's where to start anyway.
