Th eother day my 3rd brakelite stopped working.. I put a new bulb in .. nope. Another bulb. Nope. Hmm. Voltage test at the socket says 12v when I pushed the brake., HMMM. Maybe a bad socket. Nope. same thing.. Hmmmm. Did some troubleshotting and found I lost the positive to the point where it would supply 12v until under load.. I checked the wiring diagram and find the power for the lite comes from the brake switch under the dash. Replaced it and solved the problem.. Interesting.. Just wanted everyone to know if they have the same situation..