Behind the fuses under the screwed down cover is a long relay, when it starts to go it will give you such issues. It controls power to all the light. It is called a headlight relay or bulb out indicator relay. Usually the headlight part goes out first because of the draw on the board. When I got my 400E I had no indications of bulb out, but oops I had bulbs out so I replaced it with a part from a junkyard and bam it showed bulbs out. It also showed that someone had rewired the tail light probably because the indicator would not go out. I had to correctly rewire the passenger rear side marker light. about 2 and a half years out and it always works as it should. Hope my experience helps shed some light.