Brake Light Troubleshooting

[1987]

I just moved to California from Canada so I am required to take a driving test in order to get a California State drivers license. Well, I went to take the driving test this morning and was told that I could not take the test because my right brake light is not coming on when I apply the brakes.

I checked the fuses under the glove compartment and everything there seems fine. I don't think the light bulbs are burnt out because when I turn on the night driving lights by rolling the end of the turn signal lever those rear lights come on. It's just when I apply the brakes that nothing happens on the right hand side. The left hand lights work just fine. Any ideas?

Also, I have the classic "Christmas tree" dash lights issue where my warning lights on the dash flicker on when I drive on rough, bumpy roads. Could my brake light issue be related?

thanks in advance and my apologies if this issue has already been addressed in previous threads.

Mark