My 12” Garmin display is black

[billbass]

My screen is totally black. I’ve tried performing the three button presses of the power switch to force it to change to daytime brightness levels. I did the testing with a dark cover over my head and the display so it’s not a sunlight brightness issue. (I am familiar with the problem of normally not being able to see the screen in the daytime if screen was sent to the fairly dark night time brightness.)
I Have confirmed I have 12 V at the plug on the back side of the Garmin so there’s no problems with fuses or any other power source problems.

Any ideas?

 

[Hookup1]

Start with what model. Occasionally I put mine into dark mode. Tap the power button and try putting a towel over the unit to shade it. Not sure exactly how I get it back to bright but what I do above works eventually.