Interior touch screen and dash lighting

I have an electrical issue with my truck I was wondering if anyone could help. 2018 tundra double cab 5.7 4x4. My touchscreen and dash accent lights will sometimes just dim and brighten up. Only certain times. Rain or shine doesnt matter. The touchscreen will get dim then back to bright. It doesnt happen everytime I drive maybe only 3 out of 10 times or so...it happened before I got my signal lights fixed and it happens after. Any guess? I have no subs, amplifiers or anything tied into the batter that would make it act wacky. Anyone?