Old Chinese kung-fu movies are legally required to contain the following scene. A very quiet, but obviously very dangerous motherfucker is minding his own business. Then, some toughs - not necessarily actually tough toughs, but like yelly flaunty guys with flashy moves, maybe they have some kind of negative attitude towards some unchangeable attribute of the extremely dangerous motherfucker the camera keeps ominously framing - pick a fight with him or her. There is a massive ass-kicking, dozens of jerks are laid out on the floor and/or partially atomized, and the hero goes about their day.
The lesson, it would seem, is not to mess with a very quiet person who obviously spends every single night doing two-finger pushups and punching brick walls in half with their mind. I think there is an analogy to this scene when you are working on cars. It comes when you think that you have figured out a failure before you even pop the hood.
Cabin light doesn’t come on when you open the doors on your ‘73 Hillman Imp? Obviously a bad door-open switch. Oh no, says the Bruce Lee motherfucker hiding deep within the car’s wiring harness, it’s that rats snuck inside your heater core, died, and their blood mixed with coolant to produce a kind of corrosive adhesive that has never been witnessed by science. There is a massive ass-kicking, and two years later, you finally decide to just live without the dome light, snapping at your friends and family when they get a ride with you and ask why they can’t see the chapstick they just dropped in your passenger side footwell.
Even though these lessons were written for us hundreds of years ago by hit Chinese fiction authors, and only recently translated into filmic works of artistic legend, that doesn’t mean we can’t all take away something from them. Don’t underestimate the quiet thing sitting in the corner, because it will flying-dragon-kick your jaw off. And maybe search the enthusiast forums for “traction control light doesn’t go away jet li” before you get started.