My 76 Formula is having some problems as of recently with its brake lights. It has tail lights, turn signals, and hazards, but no brake lights. I've checked bulbs but not much after that.
I have replaced the switch cause the old one was bad. I checked the new one. Its all good. There also is power to the connection where the rear harness connects.Check the brake light switch. It is up under the dash where the top of the brake pedal can make contact with the switch.
Ill see if I can get a buddy and ill try it out.I would go right to the brake light sockets with a voltmeter while someone is pressing on the brake pedal. At least you can verify if the problem is no ground, or no +12 volts hot is what is keeping the lights from coming on. Then trace back what you find (no hot or no ground) is keeping the lights from working.