I know, that's why I want to learn. Garages can charge so much money to fix what can easily be done by yourself, providing you know what to do. Although nowadays, as you say, most cars have so much electronic equipment you still need to go to a garage to fix some things, they use special equipment to fix things like engine management systems and Anti-lock brakes that you couldn't buy yourself. Car engines are becoming so sophisticated you can't work on them the way you used to be able to. I look the prices of used Merc S-Classes and things like that and they seem really cheap compared to what they were new, but then they have so many gadgets on board that can go wrong and they do once the car gets to a certain age.