This is also the issue I am having with my 2017 SR5. The dimmer control switch should do just that, control the instrument cluster panel brightness and turn on the interior lights. I found that when I scroll up and click it, nothing happens. I looked at the fuses and nothing is blown. I have checked the switches on the lights to make sure they weren't in the off position. I even replaced the dimmer control switch (funny thing, I couldn't find it anywhere else except eBay, not even RockAuto had it or Amazon
) . Even that didn't solve the problem. I am just at a loss right now. I don't have the time nor the money to take it in to have it get looked at and spend over $100 to have someone tell me I need to spend even more plus labor for something that I may be able to do.
I hope you found a solution.
Grunt3327