What could be the issue if the brake lights and turn signals are not working on a 1976 Ford F250?

If the brake lights and turn signals are not working on a 1976 Ford F250, there are a few potential issues to consider:

1. Blown fuses - check the fuses to see if any have blown. If so, replace them and test the lights again.
2. Faulty bulbs - check to see if the bulbs are burnt out. If so, replace them and test the lights again.
3. Bad relay - the turn signals and brake lights may share a common relay. If the relay is faulty, it may need to be replaced.
4. Wiring issues - check the wiring to ensure that there are no loose connections, corrosion, or breaks in the wiring that may be preventing the lights from working.
5. Brake light switch - the brake light switch may be faulty or out of adjustment, preventing the brake lights from turning on. Check the switch and adjust or replace it as needed.
6. Turn signal switch - the turn signal switch may be faulty, preventing the turn signals from functioning. Check the switch and replace it if necessary.

It is important to note that electrical issues can be complex and it may be best to consult with a professional mechanic or automotive electrician to diagnose and fix the problem.