99 LeSabre No Brake lights or rear turn signals

Hope someone can help me. I have a problem with no brake lights or rear turn signals. I do have rear running lights and the third brake light in the window works. Also, I do have back up lights. The turn signals work on the dash and in the front of the car. I didn't find a problem with the fuses. Any suggestions? Thanks in advance, Sandra

Check for 12v to the bulb sockets and check the bulbs of course, if none and the bulbs are all good suspect the signal switch, this assumes all good fuses and connections. Of course also make sure the 4way flashers are not on.