The taillights don't work.
The taillights are controlled with a relay in the left kick panel through a couple of different fuses; the taillight fuse could have been blown from a trailer hook up. Check the fuses first to see if one got blown. If they are okay, then the circuit would need to be checked, to see if the relay is getting power, and sending power out of it. I recommend that you have a mechanic, such as one from YourMechanic, run a diagnostic on your taillight issue, and recommend the best path to repair.