I have a 2013 Jetta TDI with 34k. The third brake light doesn't work, I tried the flashers ... still doesn't work. I don't have a meter, so I can't tell if there's power to the wires. I did take the bulb out and ran a 9vdc battery to the leads and the light itself works. I'm stuck as to what's next? I don't want to pay a shop bookoo bucks. Can anyone help me with this?