Running lights but no brake or turn signal

Try this with your trailer battery connected. When you look at the connector from the trailer and the "index" it up, the 11 o'clock position is the hot or 12 volt to your trailer battery. Use a small jumper wire from 11 to 1 and the running lights will come on and also the tail lights. Go to the 9 or 3 position and the brake/turn lights should come on one at a time. It lights come on, the problem is in the truck, if not, the problem is in the trailer wiring. If tail lights or turn/stop lights do not work, it could be a bad ground to the rear lights.