2014 model IV: What are these connectors for?

Yes it would probably be called the wiring diagram which means you'd have to own the PDF copy of the factory manual which in a 2014 car could cost you like two or $300 You might be able to buy a bootleg copy of the PDF for about 80 or $90 in the original print versions of most of these things that only went up to 2010 in the real books when you held them in your hand in the electrical section the section is so big and so long sometimes it was in another complete book and it showed you pictures of the plugs of the business end the pin count and all of that I'm not sure what happens after 2010 when everything goes to PDF and all of that I don't know how that really works I haven't been willing to try and find out I haven't bought any of the PDF copies of repair manuals for generation 3 forward vehicles I haven't needed them thank God but yeah you should be able to get a good idea most of those plugs have numbers and names by their respective manufacturer and their pin count and all of that It's another hole something to learn I have no interest there's a guy on here that has that kind of interest that may be able to help you but there's lots of plugs dangling in a Toyota wiring harness pick any model you like Can you use them I don't know can you depends what you're going to use them for like you know wires gauge and all of that depending upon what you're going to try and drive with the circuit but yeah I would think you'd be able to make takeoffs of many of the plugs that are left dangling around on a Prius just depends how they work are they ignition controlled are they live all the time are they live with only certain components that will be your job to suss that out and figure out whether it's something you can work with they are 20 of 12 volt wires already inside of the car that are live enough of the time to pretty much hook up any of the toys people want to put in a vehicle but like anything else you can come up with many ways to do it.

 

Takes fewer words to just link to

Toyota Service Information and Where To Find It | PriusChat

which tells you all about the ways you might get access for free (if, say, a local public library participates) or for the $25 you need if you go straight to Toyota for it.