W211 Speedo not working

[DIYMAN]

Hello, when I came to start the car after about a week not running I noticed the speedo was not working, also when I started moving I had the release parking brake red warning twice, so reapplied the brake and released it again which solved that but still a speedo problem.

When I started to drive the needle would move very slightly then stay at about 5 mph, I tried stopping and switching off then reversing and after travelling about 6 miles home I parked and left the car until today. Now the speedo needle is stuck on 20 mph, I tried giving it a gentle tap but no movement.

I wonder if anyone has had the same problem and found a solution, or knows how it works, I guess it will be like a milliammeter with a return spring. I remember hearing about a lady where the rats kept chewing though the wiring when here 4x4 had been standing for while, or maybe I have a spider jamming the spring in my speedo.
Any help/advise would be much appreciated, wish I could still ask Malcolm.

 

[Botus]

4th time lucky

get the cluster repaired

Clock has stopped after dash came back to life

My instrument cluster died and I thought it was the battery so changed it. That alone didn’t bring the cluster back to life. Checked all fuses and all were fine and then one day the cluster came back to life! only problem I can find with it is that the clock is at 12:00. When I set the time...

forums.mercedesclub.org.uk

 

[DIYMAN]

So you think it is the actual instrument at fault, not the speed sensor or power supply or a bad ground connection.
I wish I knew a bit about how it works or should work.

 

[Botus]

u r the 4th person in the last week saying "my speedo stopped working..."

in one post I wrote that its NORMAL for any car made in the last 15 years to have this issue.... just check the link above
is designed to fail electronics, old 50 year old stuff still works - but magically stuff in modern cars around the 4 to 12 year mark just fails... cheap designed to age capacitors and special solder - the concerning point is 2005 to 2010 was a 15 year cycle, a lot of modern cars coming out of Germany are on a 3 year cycle