I have the exact same issue. I guess it’s just a sign of the pixels getting old...

Pushing a button or the screen usually helps for a while.

Maybe time to start an eBay search to have a spare for the future.

 

My 1998 SL500 has the same issue. Pressing on the display sometimes improves it.

 

This has been discussed many times in the past with no real fix. Swiping with light pressure along the top edge, right to left, along the surround has been the only temporary fix. I bet if anyone takes one apart there would be a way of adding constant pressure to the ribbon cable connection that would resolve the problem.
Here is a thread from 2006.. https://www.benzworld.org/forums/r129-sl-class/1285718-climate-control-display-looks-like-braille.html

 

Used to have the same issue with my SAAB 9-5 (fantastic car). There was a fix which involved taking the unit out, accessing the screen and applying a thin layer of foam along the ribbon cable contacts. Was a bit fiddly but worked perfectly.

I imagine it would be a similar solution here.

 

somewhat common problem, with (usually) a pretty easy fix. Both the E420 and SL500 exhibited this problem. Often the root cause is the square pin header for the LCD display no longer making contact with the sockets on main board. the LCD display moves outward and contact becomes intermittent.

Solution: remove the unit from the dash, take off the covers and remove the front cover over the display. then push the display back into the sockets. use a piece of foam in front of the connector if you want to keep it from moving again.

 

Solution: remove the unit from the dash, take off the covers and remove the front cover over the display. then push the display back into the sockets. use a piece of foam in front of the connector if you want to keep it from moving again.

Cheers! In this post, could you by chance circle the area where foam is applied? Climate Control Display...looks like braille-'99 SL500

Regards,
D

 

e-420 Thanks, at last, a proper fix. Any chance of a how-to with pics

 

unfortunetly when I did this a few years ago I didn't take any pictures or write down the detailed steps.

However, gaining access is pretty easy from what I recall. First step is to remove the screws holding the cover(s) on the unit. then IIRC there are plastic tabs that hold the "front panel" that covers the display on. It was pretty easy to remove to gain access to the LCD and connector.

 

I did this fix a while back... personally I don't think there is any need for foam. I put some electrical tape along the edge of the connector and over the pins to make sure it wouldn't move back into the angled position shown.

 

My understanding is that these guys will do a professional refurbishment if you so desire > Climate Controls — Beckmann Technologies & BeckTech Reman Parts

No personal experience but someone here recommended them and I stored the bookmark for future reference.