NOTE: Perform this operation at your own risk! This requires very strong skills in mechancial and electroincs repair. Before removing the instrumet cluster from the vehicle, make sure the ignition is switch off and the key remove, or you may generate an SRS error that may require visiting an authorized service center to repair.
You will need a tool to remove the cluster from the dash. Mercedes-Benz makes an official tool, and some people will claim that you must use the OEM tool or risk damaging your vehicle. The reality is, once you see what you are doing, you will understand why it’s not really that critical. I use a stiff piece of wire (cut from a coathanger), bent as shown. The working end is the small end and it’s about 3/8 of an inch long. It’s about 6 inches in length, and the other end is just over an inch, and is the handle.
Insert the tool into the slot in the cluster until to contacts the locking mechanism.
The locking mechanism grips the dash on the bottom of the cluster. Just rotate the tool slightly and continue pressing in to move the release upward and thus allow the cluster be release form the dash. You have to do this on both sides, so you might want to make two tools and use them simultaneously (though you can use just one tool and release one side at a time).
Once the cluster locks are released, remove the unit from them dash and disconnect the electrical connector. It has a locking lever that must be lifted up and then the connector can be unplugged and the cluster removed from the vehicle.
To disassemble the cluster, there are five plastic tabs, three on to and two on the bottom, that must be released. You can use your fingers, a screwdriver, or a plastic tool to gently release the tabs and pull the cluster apart.
Once the tabs are released, remove the clear lens part of the cluster assembly.
Now you need to remove the bezel that covers the LCD display. Pry outward on it as shown on the top.
Once the bezel is removed, you will see that the LCD panel is held in place by the plastic clips on the white surround.
Before removing the LCD panel, you need to disconnect its electrical connection. Turn the cluster over to the back. Press on the outer edges of the brown locking bar as shown to move it away from the connector.
Once the brown locking bar has been release, the ribbon cable can be pulled out of the connector.
With the ribbon cable disconnected, you can remove the LCD panel. Pry between the white plastic clips at the bottom of the panel to release it.
Once the LCD panel has been removed, you now need to remove diffuser and the lens.
Pry on the plastic clip at the top of these pieces to release them.
Shown in order of assembly (bottom to top), you have the diffuser, the lens and the LCD panel:
Next, the plastic holder for he LCD panel needs to be removed.
Use a T10 Torx driver to remove the two screws holding the plastic holder in place.
After the two screws are removed, the plastic LCD display holder can be removed from the cluster:
Next, remove the Mylar circuit board that contains the LED’s away from the speedometer face. It is held in place by snapping onto two plastic studs. Pry gently and it will come loose.
Fold the Mylar circuit board down out of the wat to expose the speedometer cover.
Remove the speedometer cover by prying on the two plastic tabs on its bottom edge.
The speedometer cover shown removed from the cluster:
You can now see the speedometer needle attached to the servo.
Remove the needle by prying gently from behind.
Be sure to pry against the servo so that it does not come apart.
Turn the cluster over and now you can remove the circuit board by release the two plastic clips holding it on either side.
Fold the circuit board down to reveal the speedometer servo.
To remove the cover on the servo, you will need to first shave the melted plastic heads from the two suds as shown.
A small flat head “micro” screwdriver works well for this. Just scrape the melted plastic away.
Once the studs are broken loose, you will need to pry very gently on the four retaining clips to release them. Generally, you can pry on them one at a time with a small screwdriver while lifting on the house and it will come apart.
Gently remove the servo cover from the circuit board. The main gear may come off with the cover.
Make sure that the servo worm gear is in place. Its shaft sits loosely in a slot in the plastic housing as shown.
Remove the main drive gear from the servo cover and place it into the servo housing. There is a small stud on the bottom of it that is a stop for the needle sweep. Place it as shown, which is just clockwise forward of the plastic stop in the servo housing.
Now, snap the cover back onto the servo. Fold the circuit board back over the cluster housing and snap it into place. Reinstall the cluster in the vehicle and connect the electrical connection. You will need to switch on the ignition to allow the system to self-calibrate BEFORE installing the speedometer needle. If the speedometer servo “clicks”, this means that the main gear is not properly installed. Immediately turn the ignition off, and remove the cluster and reset the main gear as shown above. If the servo does not click, then you can now install the speedometer needle, being careful to place it in the 0mph position, without turning the servo. Switch the ignition off and back on one more time to verify that the speedometer needle is in the proper position.
Now, switch the ignition off, remove the key (again, DO NOT disconnect the cluster unless the ignition is off or it WILL create an SRS error). Remove the cluster and reassemble it following the above steps backward:
Snap the speedometer cover back in place.
Place the Mylar circuit board back in place on the studs on the speedometer cover.
Place the LCD display holder back in place and attach it with its two screws.
Insert the diffuser, then the lens, into the LCD display holder.
Place the LCD panel in the holder, top edge first. Gently press it toward its top edge to allow it to snap into the clips on the bottom edge.
Insert the LCD’s ribbon cable into its connector on the back of the cluster, then snap the brown retaining clip back into place.
Place the bezel on the LCD panel, bottom edge first then snap the top edge into its clips.
Place the cluster into the bottom half of its housing, then snap the top “lens” half onto it, making sure all five plastic clips lineup properly and snap into place.
Reinstall the cluster in the vehicle by connecting the electrical cable and then pressing it firmly back into the dash opening until the retaining snap into place and it is held securely.