@donalds
Just throwing this out there for you,
since you will more than likely have another person in the drivers seat as you're testing the electrical system.
My Ex's factory original brake light switch died with a weird symptom when it went out about 6 years ago.
When you initially put your foot on the brake pedal, all 3 brake lights lit up as they should.
BUT, as your foot pressed down further on the brake pedal to bring the vehicle to a complete stop, somewhere along that downward brake pedal stroke, all 3 brake lights went out...
Found out about this condition from a city cop that was behind me minding his own business, when he saw this occur at a stop light an uphill grade. He was cool about it, more concerned about me getting rear ended in a traffic situation, so it was all good - no ticket.
After our encounter I went right to the auto parts store up the street, bought a Standard Products brake light switch, installed it that afternoon, and the problem was solved.
This is the long way to say that while testing, make sure the person in the driver's seat is holding down the brake pedal to the floor, and that all 3 lights stay illuminated, before telling them to "release".
HTH and good luck!
