[thijson]

Youtube is one of the best resources. Almost every time something goes wrong, I was able to find a video of someone fixing that part, usually on the same model of vehicle.

Scanning for codes is useful too, every manufacturer has their own scan tool. For example BMW has ISTA+, Ford has Forscan.

I think that as right to repair laws become more prevalent, there will be more information generally available.

[potato3732842]

Youtube kinda sucks for anything that isn't an enthusiast car with a big following but is old enough that it went past beater car and to "you don't see these much anymore" status before Youtube became a thing. Thankfully paper manuals are good and cheap for that kind of stuff.