Brake lights, including third, do not work.
***Tail lights and all other lights work.
***Cruise control works.
New tail light assemblies/new bulbs.
New fuses.

***Driver's side wiring connector, that connects to tail light circuitry board, has burn mark where fog light wires attach. ***Fog lights work.
***Turn signals work.

Does anything stand out to be the brake light switch or bulb failure relay, possibly?

What brake wires go through hinges?
>>>I've read only the third brake light, is.
Does the third brake light wire connect to the lower/back brake light wires and do they all connect to that burnt wiring connector that attaches to driver's side tail light assembly?
​​​​​Appreciate any opinions and guidance. Thank you so much for your help!

Mom & Son
P.S. Incredible forum. We've been able to replace tail light assemblies (were haggard as hell, anyway) and get easy access to brake switch and bulb failure relay, with your help, thus far! 🙏
We also made progress with getting reverse lights to function by messing with the shifter. (Assuming that's an adjustment, within. Will pursue.)
It's been fun and informative! Now, my son's considering furthering his Volvo mechanic education! 👍
We're just now, today, trying to get to know how to use a multi-meter and test light, at this point of our journey. Looking forward to learning!