JohnS550

Hi everyone! First post.

I have a 2007 S550 with some 56K miles. Today when i drove it the middle instrument cluster went dark. When giving the dash board a good whack on top it comes back. Another whack makes it go out again etc, etc... It could be the back lighting or the cluster itself. I noticed in the past that the potentiometer to the left of the nav screen no longer adjusts the brightness of the middle instrument cluster but i forgot about that issue since at least the light was on. Could this be an issue with the potentiometer, a loose connector, bad solder joints somewhere in the instrument cluster or something else?

I did buy a used cluster on Ebay for $500 bucks + the instrument cluster removal hooks but i'm not sure how to actually go about getting the cluster out. There are trim pieces all around the instrument panel and nothing seems to be loose enough to be simply pulled loose with a trim removal tool. One alternative could be to bring in the car to the dealer and tell him to use the used cluster should this be the issue. I read somewhere that the potentiometer could not be replaced separately so could perhaps be costly.

So, should I bring the car to the dealer or have a stab at replacing the cluster myself? I'm fairly handy (engineer) but i'm reluctant to start breaking loose trim panels just to get to the cluster - they look expensive!

Thanks!

Zerocarpileup

I would ask here and benzworld for the tear down instructions. Someone must have them. The dealer will rob you. If its just a simple task like that I would go at it. With some instructions that is. That row of buttons you speak of, just left of the nav screen, are all the buttons not working or just the adjuster poles?

JohnS550

Thanks. I just posted the same question at benzworld.com. It is just the dimmer for the instrument cluster that doesn't work. The dimmer for the nav screen as well as the nav screen angle adjustment buttons work just fine.

Also, I have received information saying that the dealer would need to re-program the instrument cluster to reflect the correct milage etc. Can anyone comment on this? Could I replace the cluster and simply bring the car in for reprogramming? Or would the dealer need to reprogram the cluster before it is installed?

MBtech1098

Dealer is unable to reprogram a used cluster as it is already personalized to the vehicle. In other words a dealer will not be able to help you.

JohnS550

Thanks. What prevents a cluster from being programmed twice? The only technology that allows a single programming cycle would be some kind of fuse-blowing which seems unlikely. Is this a limitation built into the programming tools aimed at preventing reuse of used parts? Or is it because the mileage of a vehicle should not be able to be changed?

I have also found a (supposedly) brand new cluster on the Internet. If I get this one, the dealer should be able to "personilize" it to my vehicle?

Thanks.

MBtech1098

It is VIN locked via internal coding of the control unit. It is locked to prevent milage tampering. If you are going to seek the help of a dealer, they most likely will not help you if you provide them a cluster from eBay.

S500 Man

have you tried a indy shop?

JohnS550

I have received more information from the seller of my replacement instrument cluster. He now says that the cluster is brand new and has never been installed in a vehicle. This should mean that the part never has been programmed and therefore my dealer should be able to put it into my vehicle?

Also, It seems more and more likely that it is a backlighting issue. The instruments do work even they get blanked out but it is impossible to see in daylight. I noticed this tonight when driving at dusk. Could this be a part other than the cluster that needs to be replaced? Is this a known/common issue?

Either way, I have a 30 day right of return of the replacement cluster so i'll simply bring it in to the dealer and tell them to use it if mine needs to be replaced. If it turns out to be some other part that needs to be replaced i can always return the replacement cluster.

And yes, I can also try an Indy shop. I know there are some in my area.

Thanks.