Is there a relay for license plate lights and trunk lock?

Year/Make/Model? I've never seen a relay for the license plate lights in all my years.... but there may be some vehicle out there wired that way. The trunk lock should not be associated with the same circuit, even though they are both in the rear of the car. A coincidentally occurring electrical problem in the same area would have me checking the Molex-type wire junctions ... but having said that, I always start at the inoperative device and keep testing toward the battery-fuse box since you didn't state any other electrical problems are happening. The license plate lights usually are wired in with the side markers ..... either they are bulbs in huge headlamp combo- units or individual side marker housings.

Sorry ... I see this is an Audi. My bad... but the answer stays the same.

Agree with JPV,more than likely bulb or wiring issue,they run off the same fuse and wiring as your tail lights.

Can I rewire my license plate lights to my tail lights with a fuse instead of using existing sockets that are corroded. That way when I turn on lights they come on . . I have soldered wires to the new bulbs drilled small holes to feed wire through. I'm just about tap into taillight wire for power . I think it should be fine I added small fuse . Does anyone think that's bad idea? I also tested wires in the trunk for the actuator and popper for trunk and theres no power . I was gonna originally wire in to the little plug but theres no power so I went with tail light

It's a 2002 audi a4 quattro