So I pulled the instrument cluster out and did the pixel fix with a new LCD / ribbon cable from China (eBay find). The pixels all light up 100% now, but a few problems:


A "Display Malfunction" message
All idiot lights stay on
NONE of the gauges work at all (speedo, tach, etc)
The gear selection pixels are fully lit up but are a solid square (does not show what gear I am in)


I disconnected the battery to do the repair. The connectors to the wiring harness are properly plugged in. Also I had this happen before (second repair attempt) and the idiot lights problem mysteriously went away after ten minutes (but not this time).


This is so frustrating. Anyone else have this problem happen when they pulled the gauge cluster?

 

Breaking this down, is the ribbon like for like? I can't image it would be different but its worth checking.

I would suggest looking at the plug connections at the rear of the display, check each one for any bent pins or loose wires first.

 

One or both of the plugs that connect to the rear of the instrument cluster may not be seated properly (e.g. plugged in, but not making full electrical contact).

https://mbworld.org/forums/clk-class...ix-repair.html

The electronics operate at extremely low current and the contacts can build up a thin film of oxidation, which provides enough resistance to prevent current flow. This is specially true on contacts that are not gold plated, such as used on computer boards etc.. Often just plugging and re-plugging the connectors can wear off the thin film of resistance and restore the electrical connections. In more stubborn cases, I've sprayed some electrical contact cleaner (or left over MAF cleaner), which do not leave behind any residue

 

OK thanks. I will take a look.

 

So I wiggled the plug harness and noticed the idiot lights flickering. Unplugged and replugged a few times and got the gauges to come to life, and also the idiot lights are now off, except for CHECK ENGINE. Last time I unhooked the battery and pulled the cluster that happened too but eventually went away on it's own, so I am hoping it will do that again...

 

Okay a couple of things here. You need to be carefull with unpluging the dash cable with the power on as it can cause a fault on the ECU which then needs to be reset. If you un-hook the battery you cannot simply re-connect, as you need to perform the reset procedure, i.e. your windows may be out of sync / sunroof / heater / ABS lights on etc etc.

The reset is simple though and you just need to follow instructions below.
If you unlug the cables in the future I would ensure the key is off.

A1EK’s Reset procedures for CLK 208:
Resetting car after battery fail:

Preparation Steps:
1. Make sure your steering wheel is straight.
2. Make sure your windows are all the way up
3. Make sure your sun roof is completely closed (if you have one)
4. Make sure your parking brake is released.
6. Turn off your stereo and make sure you have your stereo's Anti-theft code.
7. Turn off your heat/AC blower
8. Turn off your lights
9. Make sure your doors are UNLOCKED.

Now, disconnect battery 30 secs and then reconnect.
Get in car close the door and turn the key to position 2 (Just before you start the engine but do not start it)

1. Resetting your windows: Bring down both windows at the same time by holding the switches just before the click that brings them down automatically. Once both windows are all the way down make both switches click by pressing them all the way down and hold them for 3 secs (This lets the ECU learn that that is the end of the window track and it records it in memory). Do the same for closing the windows by holding both switches and making them click once the windows are all the way up.

2. Turn on your blower and make both sides go to 72 deg (if you have this typr of heater control) by pressing both up and down buttons at the same time. This will calibrate the ECU
3. Turn on your stereo and enter you stereo code.
4. Pull the sun roof all the way back and all the way forward then up and then done.

6. Turn all you lights on and off, including your fog lights.

7. Turn the key back to position 0.

8. Turn on your engine. You will get 2 malfunctions, your ABS and ESP lights will be on and must be calibrated.

9. Calibrate your ABS and ESP systems by turning the steering wheel all the way to your RIGHT and then all the way to your LEFT, then bring it back to the middle. Notice the two yellow lights disappear from you dashboard.

10. Let your car run in idle for about 5 minutes and then take it for a spin. Remember your ECU is still getting all the readings from all the sensors on your car so drive slowly first then faster... and so on.. you are basically teaching your ECU how to handle your car.



Throttle Reset

1. Get in and shut the door
2. Turn key to position 2 (just before you start the engine).
3. Press the gas pedal to the floor... past the kick down point...
4. Hold the pedal there for 15 seconds
5. After 15 seconds while foot still planted, turn the key off but do not remove it.
6. Release gas pedal and wait 3 mins. Do nothing, you should here a click near key at 3 mins.
7. After the 3 minutes start the car and drive off normally... you should notice a difference in the shift pattern and smoothness.


Service Reset
Turn the car on to the 2nd key position, all the way ON, but do not start it.

- Then scroll through and find the A/B Service notification. Hold the "R" or reset button on the dash. After a few seconds a message will display on screen asking you if you would like to reset the service notification. Once this happens let off of the "R" button.

- Press and hold the "R" button one more time until the reset is complete.

Valve Reset:
(move valve with finger off 90degrees, turn key to 2nd position, let valve close and open, wait for "click", turn off key, turn back on for 45 secs during which time the valve will close and open again, key off (Not been able to make this work)
Trunk Release:
Remove drivers fuse panel, pull 4 fuses on left 7.5A and 5A, wait few secs and replace then try door unlock switch to see if it works, this will tell you if alarm is deactivated. If not try other fuses.
Passenger Mirror auto-dip reset:
1- Turn key to position 2
2- Select reverse, adjust mirror down so you can see kerb for reversing etc.
3- Press Green store button on drivers door control next to the seat adjustment for a couple of seconds, then within 3 secs press the mirror control again just once in any direction, mirror is now stored. Return to Gear shift to Park.
4- Wait 17 secs mirror will return to normal position.
5- Select reverse and test to make sure it dips ! DONE.

 

This is excellent and very comprehensive information. Thank you so much. One question though... what is the "valve reset" I don't understand what component this is talking about.

Thanks!

 

If everything OK, except the CEL, which may be lit due to a stored fault, caused by the poor harness connection to the cluster, it may turn itself off, after 3 cold engine starts.

 

the Valve reset is the airflap dump valve or release valve from the supercharger.

Serndipity is correct, the car will clear a fault by itself if corrected and started a few times afterwards successfully.

 

The car is in the underground garage for the winter, but I will give this a try. I'll let you all know if it ever does go out or if I have to take it to the shop.