I recently had the back light go out on my unit.
you can shine a flash light next to the screen and see the images.
I have already done the soft and hard reset and did check to see if I bumped the dimmer setting, it is all good.
called lowrance and really got nowhere with them because the unit is considered not serviceable dues to its age (bought new in 2016). and I did not want an Elite 12TI for a replacement of $1200.
I know there is a LED strip that lights up the screen but I can not find a replacement. would like to see if this helps my issue before I set the $1k unit on the shelf to collect dust. any advice is appreciated.
Sorry to hear about your bad luck. I am not aware of a lighting strip behind the screen, I have not had the case open on a 12 but I have a 9 and feel sure the component design is the same. If you have not opened it up, this PDF will give you a visual of the insides.
I try to drive as if my 16 year old Grandson is following me
Speak as if he is listening and act as if he is watching