Modern Vespa

My 2009 Mp3 250 suddenly developed an issue that the local dealer has been unable to resolve. The motor turns, the screen is yellow (no info displayed), the scooter does not move when throttle is turned, and tilt remains locked. All fuses were checked and are ok. Scooter has been at the dealer for 3 weeks! HELP please! The issue is very similar to this posting:
MP3 400 no info on display, starts but won't go

Has the seat sensor been tested?

Yes, the seat sensor was tested. No problem there. Mystery continues....

ignationswitch needs replacing the inturnal connectors are most likely corroded

Thanks Maksor. That's not it. There is no corrosion.

So the engine is running, your butt is on the seat, display is normal with no warning lights right?

When you twist the throttle what happens exactly?

Display is not normal.
Am having the same problem as the attached video clip.

take the ignition switch apart did have 3 or 4 customers with the same problem no display
and an other ignition switch solved the problem

Problem is the part that is corroded isn't sold separately its between the barrel and the plug

Thanks Maksor. I passed on your suggestion to the repairman. Waiting to hear back.