2006 630 D12D Instrument cluster flickering like crazy

Greetings fellows, I need help with this please. The problem started about a week ago.. The dash cluster in my VNL630 with D12 engine sometimes flickers like crazy. Sometimes the idiot lights flicker on and off and the gauges are still working. Sometimes they flicker on and off as if the ignition was turned off and back on, with the gauges doing a test sweep. Then, sometimes the display is black and the gauges still work, then other times everything quit with the gauges frozen in the last position they were in. In this case I have to remove a battery terminal to get it to work again. Some times the engine will stumble, but no problems starting. All other electronics work as they should i.e. Head and park lights, interior lights, radio, wipers, blowers, and power plugs, all good.
It does these things sporadically, with no pattern noticed. It has done it idling as well. No difference on bumpy or smooth roads.

I have done searches and most info point to a faulty ground. I have cleaned all the battery thermals, + and - with no change. I clean the two ground terminals on the top left firewall. I check the fuses under the dash cup holder. I found nothing, but then I didn't know what I was looking for there anyway.
My search turned up others with the same problem, but only one posted his fix, (clean battery terminals) but that didn't work for me.
Please help, as this is starting to get aggravating. Pleas accept my thanks in advance.

 

Well, I changed the ignition switch today, still have the same problem. I will look around the under the dash, and check the chassis and engine grounds. Thanks for your help. If you think of something else, please let me know.

 

Thanks for the reply. This morning 5 minutes after I started the truck, it started to flashing again. The gauges were not working and the idiot lights were doing a steady flash every two seconds. When I shut the truck off while unloading, it flashed with the ignition off. It didn't stop till I disconnected the battery terminal. I pull the dash cluster out, and all connection were tight. I check and cleaned the ground on the alternator and two of the grounds on the firewall. I didn't get to the rest because I had to leave the dock. I'll go under the truck to check the engine ground later this week. Whatever it is it is doing it longer and more frequently. If you have more idea and suggestions, please share them with me. I'm going nuts Thanks

 

I'm at the end of my rope with this problem. Here's what I've done:
1. replaced ignition switch
2. Checked and cleaned battery cables and terminals, + & -
3. Checked connections on dash cluster
4. Checked and clean chassis ground
5. Checked and cleaned all ground connections on top firewall.
6. Ran separate ground cable from battery to ground stud on firewall.
7. Checked and shook ( did not remove) wires at pass thru
8. Checked and cleaned positive cables on bottom of pass thru

It seems that every day it does something different. Yesterday the engine would stall while driving. Today it's not stalling, but the idiot lights are on a steady flash every 2 seconds, and the gauges are frozen in the last position they were in when it started acting up this morning.

I want to thank everyone for the help so far. But if you have more ideas please share before I can get enough dynamite to blow this thing to h@ll.
Thanks again

 

Thanks, but I don't get up Chicago way anymore. I run east coast, mainly between Washington, D.C. And Atlanta or Jacksonville. But I'm starting to think the cluster is bad. The display which shows the average mpg is stuck on 99.9. And sometimes the cluster telltale lights keep flashing after the ignition switch is turned off.
The gauge test shows the gauges doing a full sweep without any sticking.
If the cluster is bad, is there a fix for it at these companies who "rebuild" them?
If a got a used one ot a new one, would a dealer have to program it?
Would the remedy that @Kanu spoke about in the above solve the issues?
Thanks for you help.