gocarz

Hi guys !
Backstory is that I got a 2008 German C63 that was exported to the UK when new. The owner was an emirati living in London.
In 2008, he had the cluster changed at a Mercedes dealer for a UK one (reading MPH) :

*not my pic ^^
Fastforward to 2017 when I buy the car and it goes to France where I live. I'd like to get the KMH reading for the physical speedo (digital screen allows you to have both readings fortunately) :


**nor mine
I bought the OEM kmh speedo off ebay :
The weird part is that the needle doesn't move the same way between mph and kmh clusters.
After some research, I spotted one similar post : https://mbworld.org/forums/c63-amg-w...luster-km.html

There seems to be something that can be done with reprogramming but information is quite scarce and most specialist I spoke to seem to think I'm doing some kind of dodgy stuff.
What would you do apart from changing to a brand new OEM cluster from Mercedes (which was paid once in 2008, got the invoice for that lol) ?

Hope this is clear,
Please let me know if you need more info,

Cheers,
Zak

Diabolis

Correct - the km/h cluster is linear in operation whereas the mph one is not. The cheapest way by far would be to get a km/h overlay that properly matches the numbers to the way the needle moves on mph clusters like this one: https://www.heiler-tachodesign.de/Sp...AMG-Mph-zu-Kmh.

sventastic82

Yes that would work the km/h cluster in the link matches the mph.

You can see the difference at the 12 o'clock position which is 80mph for the linked cluster and 130km/h for the original one.
The cluster OP purchased has the 160km/h at the 12 o'clock position which needs to be coded. (Or you just keep it and never get a speeding ticket.)

gocarz

Thanks for your answer.
I already spotted this tacho background but it's not original per se (no AMG logo).
In the event of a complete Speedo cluster change, would I have to buy an new unit from Mercedes ? (Last invoice in 2008 was £1800 so more than $2k)
Cheers

Diabolis

There is no OEM instrument cluster overlay that Mercedes makes and/or sells separately. Whatever you bought form eBay are either parts that have been removed from a used cluster or are replicas. Mercedes will only sell and replace the entire cluster, which they also need to code for your vehicle and provide all the paperwork to the ministry of transport / motor vehicle department in your country (a cluster change needs to be registered on the title of the vehicle in every country I know of precisely because of the odometer reading and the possibility of fraud). As you have already found out, no legitimate shop will ever touch the cluster coding as it is illegal and punishable by heavy fines and prison sentences.

While you can replace the overlay with whatever you want, the company making the overlay can't legitimately put any markings on it which are trademarked, so they can't print a Mercedes or AMG logo on it.

gocarz

I wasn't clear on my last response. I do understand Mercedes will not sell elements separately. I've never heard about anything regarding an administrative requirement of informing of a cluster change (at least in Europe).
Regarding the fact that no legitimate shop would touch the cluster coding...
I'm not asking them to change the mileage but only to convert the needle "movement" from mph to kmh so nothing that can be related to fraud.
Do you reckon anything (hardware) is different between mph and kmh clusters ?
If it's simply a software change, I don't see how no one could reprogam this.

Thanks

Diabolis

The odometer on every vehicle is in the instrument cluster. If you could simply replace the cluster without informing the authorities, you could put 200,000 km on the car, buy a new cluster and drive the car for another year, and then sell the car with a cluster that reads 20,000 km - and no one would know that the actual mileage is now 220,000 km, not 20,000 km. That's why replacement clusters need to be registered with the authorities.

I don't know whether the hardware is different between the imperial and metric clusters (I suspect not), but no one other than Mercedes can legitimately reprogram it, and thus no legitimate shop would be even interested in tinkering with it because the penalties are huge. You have to go through a dealership or authoried service center, and they have already stated that the only way to accomplish what you're asking is to replace the entire cluster.

sventastic82

The odometer reading will not change by just changing the cluster. The mileage is stored in two places, cluster and ignition module. Another custer will not work it has to be programmed to match the mileage in the ignition module.

Diabolis

The cluster odometer is always considered to be the authoritative one, even if on some newer cars (but not all) the cluster has to be coded to the vehicle and/or the mileage may be stored elsewhere. Think back to cars with mechanical odometers. ECUs can be changed and reprogrammed without restriction - it's always the cluster that shows the mileage.

sventastic82

The cluster will not show a mileage if it’s not matching the stored mileage from the ignition switch. It will show a blinking line. Also when the ignition switch is changed it will need to be programmed.

All newer cars with a digital cluster have the mileage stored in multiple places. Some store it in the light module or ecu.
Yes, they have to be programmed. We can agree on that.

Sure, the old mechanical clusters were the only place where the information was stored. Because it was mechanical. There was no way to store it anywhere else.