Toyota sequioa headlite problem

I have an’02 Sequoia & when it rains my headlites won’t turn off. I have to pull out the main headlite relay to kill them.

I’m not familiar with the wiring for your car but there may be a module that controls the relay for the lights and the trouble is with the module or possibly a corrodid connector. Moisture on a corrodid connector can cause a alternate path to something that it shouldn’t be. The relay may also be sticking but I doubt it. If you have another one to swap it with you could try that.