Hello!

So about 2 month ago my SRS light came on when I got home from work and would not go away. About 3 weeks later while driving at night, I noticed my cluster went black. RPM, MPH and Fuel (1/8 light went on) were not illuminated and got a message saying "defective instrument". This went on for about 5-10 seconds before everything went back to normal. About a week later it happened again, but this time with the radio turning off and climate control turning off. 5 - 10 seconds later everything was back to normal. As the weeks went on, the issue became progressively worse. It happens a lot more often and will last longer than 5 - 10 seconds from time to time. Sometimes the cluster will go wacko then go back to normal then will go wacko once again. One time while walking to my car and wanting to unlock it with the key fob, the car would not want to unlock. Looked inside and saw the high beam light on the cluster was flashing. Stood there for a good 5 seconds and it went away and I was able to unlock the car and this also progressively got worse as the weeks went by. I noticed when driving and when the cluster completely goes out of wack, I pretty much lose command to everything. Climate control, steering wheel buttons, radio turns off, windows, signal lights, etc. Last Wednesday, I was driving to grab some dinner and the cluster was going crazy nonstop. Got to my destination, turned off the car and saw the blue high beam light flashing repeatedly and could not clear any codes on the screen with the Up/Down arrows on the steering wheel. Waited a few minutes and the cluster went back to normal. Turned the key to turn on all the electrical power and everything was fine. Got home and disconnected the battery to reset the cluster, woke up the next morning, connected the battery and the cluster worked fine with no issues. I could unlock the car completely fine. Drove to my cousins, cluster didn't act up once and we took the car to a shop called Euro Auto Spot (bunch of friendly dudes and a bunch of clean bimmers everywhere lol) for diagnostics. Left the car there to go under diagnostics and got it back today. Was told that they couldn't source out any issues because the cluster did not act up the whole time while it was there/going under diagnostics.. Got my car back, was told to drive it for the weekend and see if it acts up then bring it back monday, drove it for about 15 minutes and the car was totally fine. Got to an empty parking lot, turned off the car, took out the key and bam, high beam light flashing on and off on the cluster. Couldn't lock or unlock the car with the key fob or with the button on the dash. Powered on everything electrical without the car being turned over and still nothing. Buttons, windows, everything just didn't want to work. Turned over the car, took about 5 seconds for the cluster to recognize the car was on and everything worked fine. All the functions worked completely fine, drove the car for about another 15-20 minutes with zero issues until I turned it off.. Then all hell would break loose..

I've searched around and found out a guy with a W209 had the same issues as me and when he got his cluster replaced all the issues went away.. So I'm really hoping that I was just need to replace the cluster and it's not anything more complex and crazy expensive.. So if any of you may have any idea what the source of the problem is, please let me know! It'll be greatly appreciated and I thank you in advance!

 

If it's not your instrument cluster, It's going to be your rear SAM. Due to the flashing lights, doors not locking/unlocking, etc., I'd be more suspicious of the SAM.

What year is your C240?

 

Thanks for your reply! It is an 02'
Just to clarify just in case there is some confusion, it isn't the actual high beam lights flashing, it is just the high beam symbol on the cluster.

Edit : I just found this thread https://mbworld.org/forums/c-class-w203/459611-2002-c230k-electrical-disaster-front-rear-sam-designation-pin-outs-d2b-most-2.html

These were the exact issues I was having before I disconnected the battery and took it to the shop. I haven't driven the car since yesterday and the issues that happen while driving hasn't happened, but when the car is off is when the issues seem to come back. I will try and take out fuse 64 later today and see if any of the issues come back. Hopefully it might just be a malfunctioning radio causing a miscommunication to the CANBUS. I will update later.

 

I really couldn't give you a confident opinion on whether it's the SAM vs. the cluster because I have never had a similar problem, so I know little about the symptoms of a cluster failure. However, I have read a number of threads suggesting that similar symptoms are indicative of a rear SAM beginning to fail.

I recently had a problem with my cluster going dark (after doing some A/V rewiring). It turned out something tripped the CANBUS. I had the ICU reset and problem solved. However, I didn't have all the same symptoms that you have - mine were a dark cluster and my headlights stayed on.

I noticed you are in San Diego (as am I!) - I highly recommend this place right in between Chula Vista and National City (a street behind the Chula Vista DMV) called South Bay Autohaus. Those guys are top notch! Also, there is a W203 cluster listed for sale in the local Craigslist ads (not mine, but in case it ends up being your cluster you might want to search for it). If it's your SAM, I have a spare that I could work out a deal on it for you.

 

Okay, quite update. I haven't been driving the car all too much the last few days, but I've noticed that with the radio on, the car seems to go crazy way more often than it does with it off. I have a meeting tomorrow, few errands to run and I will be driving the car without the radio on the entire day. I will hopefully update again to see if the radio is the culprit. From what I was reading off of the thread I linked above, the radio could be malfunctioning and causing a miscommunication to the CANBUS so hopefully it might just be the radio that would need replacing? I'm leaning towards the rear SAM being the issue though.. But until then I will let you guys know! Thanks for the help Euro! I appreciate it!

 

I sent you a pm