in my case yes. I know how to use a multimeter and know what to stay clear of when working on the cars.
I do- after 17 years doing this I know a fair bit about the cars I do. if I do not then I go to a local dealership and talk to a tech about it ( this is the case with a new benz , porsche,volvo etc.) for a few minutes then go prod with multimeter.
- bah, let that info into the wrong hands- would you like your gone with info found on the net. its that easy.
trust me I get blamed for things I DIDNOT do daily to cars. its easier not to give info aout in most cases and not have to deal with it.
the diagram you linked to is incorrect btw.