Congrats on the new-to-you TT. I just got a Jayco myself and don't really know. My guess is, no there is not.
Are both sides out or just one?
- If just one check the bulbs on that side.
- Inspect the connectors on both the TV and TT looking for bent broken or corroded contacts.
- Inspect the TT cable looking for breaks or spots that may be worn through from rubbing or being dragged.
- Do you have or can you borrow a multimeter that can be used to check voltages?
- If so check your TV wiring harness to make sure it's sending the signal.
- check the bulb sockets for voltage.
- If you haven't found the problem yet start tracing the wires looking for the break.