[Mike V. Florida]

Here are the facts:
1. Electrically, everything on the car works as it should except for this problem.
2. When I depress the brake pedal with nothing else on, neither brake light works.
3. If I turn on the cowl lights or headlights, both tail lights DO work.
4. With the cowl lights or headlights ON, if I then depress the brake pedal, the driver side brake light comes on, but the passenger side does not (and further, the passenger side tail light then goes off). All bulbs are ok since I've tried them on both sides, and have also tried new ones.

First and foremost welcome!

Do you have this wiring diagram?

If you look at the drawing you will see the one part that is common to all the lights. The light bail on the bottom of the steering column in the engine compartment. Did you knock it loose?