The internet knows everything and Google certainly does. Things you can’t find on the web don’t exist. Oh, and everything on Wikipedia is correct. At least as far as car lighting goes that’s not true. Here are some examples.
In forum discussions dealing with questions on retrofitting xenon lights, people like to claim that headlight washer systems for 35-watt xenon lights are only compulsory in Germany. In actual fact, they’re compulsory in all countries complying with ECE regulations. These regulations apply in the whole of Europe and in many other countries. North America is the exception, where xenon headlights neither have to have automatic headlamp leveling nor a headlamp washer system.
The headlight covers are often the subject of a seemingly useful tip. Unfortunately, they sometimes go matt for various reasons. Or they’re simply broken. Remedies in the form of new headlights are expensive because headlight covers in later models can usually not be replaced separately. They’re firmly glued to the housing. So at this point the baker technique comes in. Following a tip offered in relevant forums, the headlight needs to be heated to an extremely high temperature in an oven so that the glue goes soft. Then the cover could be taken off and replaced by a new one.
That’s bad advice for several reasons. Firstly and most importantly, headlights are not built for oven temperatures. Not only the glue will go soft but also the housing and reflectors, and they can get distorted. The headlight would then never be tight again and the distribution of light would be all wrong too. Besides, headlight manufacturers don’t supply the covers or glue as replacement parts. It’s doubtful whether the ones you can buy on the internet would meet the high quality standards of the automotive industry. And let’s not forget the electronics which are built into headlights more and more often. They’re definitely not designed for the oven either. So it may happen that a new cover will make your headlights look super stylish, but that some of the functions will get lost on the way.
Very often, both amateurs and experienced hobby mechanics want to aim the headlights themselves. That’s no problem, but only with the right equipment consisting of an headlamp aimer and an entirely level and flat work surface for the whole car. Oh, and you’d need the skills too. “I want to aim my headlights. Where are the adjuster screws located?” says it all really. It’s a fact that aiming them in front of a wall is too inaccurate. Either the headlights dazzle afterwards or the range suffers considerably. So adjusting headlights is a job for a mechanic, as is wheel balancing. You wouldn’t do that either, would you?