Brake lights/wiper issues?

Looking at the wiring I would test the stop lamp relay, if it lost the ground connection with the key on the top light would work but nut the main lamps. The ground it uses is a common failure point as well. the one at the rear of the right-hand cylinder head, which is also the one the wipers use. Could be a corroded connection and these are the first signs of failure. It's also possible that the engine ground is corroded and causing the ground to allow some current flow which stops the relay. The relay is mounted to the cowl panel on the right-hand side, basically above the ground connection it uses. In the third image you can see how the power from the stop light switch goes directly to the CHMSL but passes through the relay to power the other lamps. A fast way to tell if the relay is the problem or it's ground would be to find the relay mounted to the firewall and run a second ground to it as a test. If the lights now work and the wipers work, go over the grounds located on the rear of both cylinder heads.