Now how fast am I really going?!
(OK so the picture shows it working, because I took the pictures after fixing the problem)
Sometimes it starts working again at random, most of the time its black.
Don't bother taking it to the garage. Don't fear having to completely remove the dash to fix it.
In about an hour (or less) you can fix it yourself, no need for parts, no special GM tools!
You will need:
T15 Torx screwdriver
7mm nut driver
soldering gun (optional)
1.5 elbows in each arm (or just one arm will do)
Step 1: Remove gauge bezel
Pull bezel to remove (bottom has spring clips)
Step 3: Remove even more screws
(This step eliminates the need to remove the entire lower dash panel)
Then the cluster ring/trim
Then the gauge face trim.
Then the tinted speedometer lens
Then you can remove the cluster itself through the dash opening.
Remove the four screws to remove the display.
Be careful it is actually made of GLASS.
Don't make them like that anymore.
There it is!
The little spring contacts has driven right into the solder contacts on the back of the display circuit board.
This loose connection causes the digital display to be faded or completely blacked out.
The next steps will be what I did to repair them. You could try just cleaning them or slightly sanding them but the material is missing and in my opinion the best way would be to build up the contact points to press down the spring contacts in the cluster base making a better connection.