No tail or brake lights on my 75 Ford F100. Turn signals and flashers work, headlights and marker lights all okay. I replaced the Headlight switch and checked the grounds at the lights and made sure the bulbs were both good and making clean contact. Any ideas?

. Test all under hood and under dash fuses with a test light or multimeter:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-3.html#post252145

. Spray the brake light switch with WD-40. If the problem persists, replace the brake light switch.