When stepping on the brakes, my brake lights go on, but my 3rd brake light doesn't work. I put in a new bulb, checked the fuses and changed it just in case, and still, no 3rd brake light. Someone know the reason why? I'm thinking it could be an electrical short somewhere.

 

If it was a short you'd be blowing fuses most likely. Check for voltage at the socket to rule out bad bulbs, but I suspect you have an open circuit somewhere and/or a bad connection on either end. If you're up to troubleshooting it yourself, the wiring diagram would be the place to start. I really don't know where the 3rd brake light taps it's power from or the route it takes.

 

All the brake lights are on the same fuse, so that isn't the problem. Like Rick said check for power at the light socket. If there isn't any you'll have to find the bad connection, most likely inside the liftgate somewhere.

It's also possible the new bulb was dead when you got it, so if you have a meter check the resistance of that.

 

Thanks for the tips guys. I'll check on the connection after work.