We had a N5 that that would happen, seems to me we replaced the breaker and it fixed the problem. Good luck, it is hard to drive straight in the dark isn't it !
G'day John, I used to run an N5, I didn't have any problems there but we ran 40 series John Deeres and had trouble when we started fiddling with the lights (higher wattage) it seems as though the breakers get weak and replacing is the only solution. Good luck