Csaba76

My 2000 S500L ABC had a Instrument Cluster (IC) with a flickering backlight problem. On 1st of Aug I had to replace some bulbs in the tail light and suddenly I found that the IC stopped working (no backlight, no gauges, no LCD, only SRS and CEL). Fuses were OK.

My first thought was that if replace the VOGT and all SOT404 MOSFETs (assuming while some of them are the drivers for transformers, the others are for providing power supply for the IC) I can fix the problem, but I failed.

I bought a second hand IC (UK instead of the original EU) that works well except the followings:
- no ODO only dashes
- display defective error shown on the LCD
- no TEL in the menu
- no stationary heating in the menu
- no Voice Command (the function is working)
- no ABC messages (no messages if the the ABC mode is changed, the car has the "chime on wavy surfaces" issue, but as I recognized, the IC displays defect related with the AIRMATIC.)

It's clear for me that the second hand IC is from a car with other option level (no TEL, no stationary heating, no ABC).

I called the local MB Service Center, they told me there is no way to add/change the new function for the installed IC from the original one.

I found that basically the 2 ICs are the same even the PCB version - so option level should be coded in the firmware.

What if I replace the AM29F002NBT-120J EEPROM (possibly with the 24C06) from the bad IC to the working one?

Will the original functions available again?

Any comment and advice are welcome.

Regards,
Csaba

ibeforreal

There was a recall on the instrument clusters several years ago because of the problems you are describing. Perhaps the previous owner (if it is not you) never got the recall. There are plenty of post on here in the Encyclopedia about the IC problems.

tusabes

Why don't you send your original cluster to the guys who repair them

Csaba76

The problems are the following:

In Hungary, there are only several shops that can repair mainly the backlight and it costs up to 260USD.
The VOGT was free for me and the total 5 pcs N-channel MOSFETs were 17USD including shipping from Farnell.
Because of the above I decided to try to fix the IC myself, but failed.

The used IC was 85USD.

It would be the best if a shop could adjust the IC to the car, instead of swapping the EEPROMs.

Regards,
Csaba

fxdeebee

Its a bit unclear if an instrument cluster can be programmed more than once. This is what the MB dealer may be referring to in "they told me there is no way to add/change the new function for the installed IC from the original one."


However, if the EEPROM can be overwritten a second time...in STAR there is a very simple method to read the old IC, store that info on STAR, replace IC and then write that info back into new cluster.


The idea of swapping your EEPROM into the UK IC may work, if it is socketed. The process of desoldering / resoldering it may trash it though.

Csaba76

The original IC is absolutely dead. There is a B1780 code in the Comand engineering menu (faulty CAN communication with the instrument cluster), so I can hardly imagine if the data can be accessed via Star. Desoldering the EEPROM is not a big deal.



On the other hand I can compare at least the voltage levels between the two ICs at certain positions before the swap, maybe I can find the defected part.
Also I have an independent MB service center, on Monday I'll ask them whether they could reprogram the IC based upon the VIN.

So I try several parallel ways for the success. If anybody is interested I can post the results.

Regards,
Csaba




AM29F002NBT on a W220 instrument cluster