The third brake light was not working. I replaced the bub, and still not working. I checked for voltage on the terminals, and, NOTHING. Then, I pulled out the whole unit. The electrical connections were bad. Not the ones you see when you remove the plastic cover, but the connections under the part that the lamp housing assymbly go into. One of the connections was melted. The connections seem to be a poor quality desing. I had to bend one of the "sliding" parts so that it would make connection. Anyway, I got it all back together, and it works just fine now.

Stuart