Upgrading my old factory radio to newer touchscreen (question)

If you're looking at 2015 (or anything 2012 or later, the refreshed version), there are two variants of the touchscreen radio, the 6.1 inch (?) with the CD slot above the screen, or the 7 inch with the CD slot behind the (folding) screen.

You're probably in uncharted territory unless you can find some aftermarket car audio place that sells the right adapter harnesses; you can look in both years' wiring diagrams (more info) and find the part numbers and pinouts for the connectors you've got and the connectors you'll need. Each diagram will show variant wiring for the different radio options from that year, so make sure you're looking at the right variant in each diagram.

If you get the radio from a salvage yard and they've chopped the wire harness a few inches back from the connectors, you'll save money over buying the connectors and terminals at the dealer.

Then just get out your crimp tool or soldering kit and your green eyeshade for squinting at both diagrams and going "this wire goes to this one, and this one goes to this one ...".

If you get the 7 inch replacement, you'll also need the JBL separate amplifier that goes under the passenger seat, and take care of wiring to that.

 

The interface between newer Prius upgraded HU and the base radio makes the task very difficult. It's much easier to use a Kenwood or Pioneer with adapters. Look at my Media page to see what I and others have done with 2010 and 2011 Prius II base radio upgrades. You don't have to go full tilt boogie either.