Viewing window showing audio and backup camera problems

My 2019 Tundra 1794 has a continuing sporadic problem with the inside viewing screen. Without warning it will go almost completely dim and then come back on, only to go off and on again sporadically. Had it to my local dealer twice. Once they replaced the amplifier, but nothing on the dimming. Recently when I took it back again I was told they couldn't reproduce to problem. Have 33k on it now and don't want it to go out of warranty and then they figure out what's wrong. HELP?????

 

Check the ground wires, battery terminals first.

 

I've got a new to me 2020 and I've had my screen go dim and light back up randomly a few times, but seems to only happen when the headlights are in auto mode. Maybe the sensor is confused thinking it is dark out, and so dims the radio screen? Might be something to check if they didn't already check that.

 

Thanks

 

What exactly do I check. Ground wires attached to battery?