no trailer lights on 1999 Lexus RX300

I have no lights to my trailer. There is a small unit in the back of the car where the taillight wires are tapped and routed out to the trailer connector. There is no power to the connector. I assume the unit has failed. Can I simply splice into the car wiring for the trailer connector?

Asked by for the 1999 Lexus RX300
My suggestion would be to get a wiring diagram before attempting to do any splicing. Better to take it to a shop that installs trailer hitches and have them do it.
1 more answer
My car had wet rain and old.