Hi @paula62370
Seems as though there's a problem with the digital screen, its connection to the control board or a loose/corroded cable connection to the control board.
You would have to remove the display panel board from the dishwasher so that you can check.
If it is the digital screen itself that is the problem, it may be very hard to source the actual screen so you may have to replace the entire board as I doubt that you would find a replacement screen. Although you could check on the back of the screen itself to see if there's a make and model number on it and then search online using that information.
Finding parts for the dishwasher, using the model number you posted drew a blank, although I did find some [https://showhomestyle.com/lg-mez64589015-dishwasher-manual/|information] that suggests that it may also be known as an LG ''LDS5040ST.''
If this is correct then the control panel board is part # [https://www.ebay.com/itm/124744848351|EBR73742804] (cheapest supplier found, example only)
If you decide to replace the board, check what the part number of the board is in your dishwasher, to verify before ordering. It should be printed/ticketed on the board somewhere. Then search online using the ''part number only'' to find suppliers that suit you best.
If it is an ''LDS5040ST'' model, then here's the [https://research.encompass.com/ZEN/sm/LDS5560ST.pdf|service manual] that may also help.
Go to p.19 to view how to dis-assemble the control panel assembly.
I also suggest that you download the manual and keep it in case you ever run into any problems with the dishwasher in the future (hopefully not) as it shows how to troubleshoot any problems based on any error codes that may be displayed.