Not my car that's got the problem, as I dont' even own a Jetta, but I'm hoping someone could help out on this board. My friend's MKIV Jetta TDI's signal lights are blinking really fast. I recall reading about how this is a pretty simple problem and could be easily fixed. Does anyone have any tips on what's wrong? The headlight bulb blew out too, does that contribute to the problem? Thanks!