Rear brake lights not working,but third (cab) brake light is

check the connections at the brake light switch use a static tester to make sure you have voltage going out. the two brake lights { the cab and the regular rake light are on diferent fuses. if they are all right check with a tester if you are getting voltage to the rear stop lights at the sockets.

Ok. I checked the connections at the brake pedel. There are 6 wires there. Five had power (12 volts) when i didn't press the pedel and 1 had power only when i pressed the pedel.And I also verified that the fuses are good again. Here's the weird part.. I tested power at the rear stop light sockets i had no power when i wasn't pressing the brake, but when i pressed the brake i would get a very small reading... like 1 volt or so. That doesn't seem right to me... shouldn't there be the full 12 volts or something?

i ended up taking it to the shop. they said it was both bulbs that were bad. i'm just not to sure of that cause i know i checked them with new ones and didn't have any lights still. they also said that they had 12 volts to the sockets where as i only got about 1. not sure what changed with that but they got it working. :D thanks for the help m_j_ritzel. i really appreciate it.