Oem Wiring diagram and pinouts

Whated to ask that website is the best for oe pinout and diagrams

Forums are usually a good route, or you can pay for a subscription to AllData or Mitchell or ProDemand etc and use theirs.

In my opinion OEM diagrams are usually the best but they vary a lot from make to make. The paid options are usually a standardized format which is nice if you like the way they have done it. They also have some interactive features and added tips/documentation that can be helpful to understand functions or test.

But they are pricy

With right to repair rules in some countries, manufacturers need to make manuals available to the public (although they can do it behind a pay wall)

A lot of manufacturers allow you to pay for day, week or year access to repair manuals. For instance toyota, subaru, nissan, audi, volkswagen, bmw and many others have portals you can pay for 24 hour access to, in which you can print/download all the wiring diagrams and other manuals you need for a vehicle.