About an hour into my two hour drive tonight I noticed the lane keep assist button was no longer illuminated so i pressed it and got the message "lane keep assist system unavailable." I tried cleaning in front of the camera behind the rearview mirror and turning the truck off and back on. I could not get it to work. I am new to this forum and was hoping someone would have some advice on what to do. This is a 2016 sierra denali 1500 with approx 50k miles so of course it is out of warranty.