2014 cherokee limited no trailer lights
 

My wifes 2014 cherokee limited has the factory tow package. We've used the car to tow for years now never had a problem.
Recently went to tow again and no trailer lights.
I checked with my meter and with a known working trailer and nothing.
I've read about the dealer having to turn on the option in the computer but they used to work so I'm not sure thats it.
The TT lights seem to be fed thru several fuses, all of which look ok ( I have not pulled and checked them yet but I dont suspect fuses because other features seem to work).
Another suggestion was a bad ground. I saw a pic of a large braided ground strap that corroded on someone elses jeep causing problems. On this note.. her radio now has a clicking sound consistent with with blower speed.
Any ideas?