Dear W203 owners: First of all, let me apologize in advance because I'm a noob here and this is my first MBZ (and this is my first real post). Thus, I'm ignorant of what may be very obvious to you. I have also searched the threads extensively with no apparent answer. Also, thanks in advance for your help and input. That being said, here's my problem:


The patient is a 2002 C320. Last night I managed to kill my instrument cluster. Nothing on it works - lights, MFD, gauges, turn signals, etc. Also, now my headlights won't turn off. I'll give you a little history of what I have done since I purchased the car last week.


Last week I removed the stock head unit (Bose) and installed a Kenwood DNX 9990HD. I wired all the door speakers to the head unit, and I installed a small amp to drive the rear deck sub. Everything worked fine. Next, I installed a Metra SWC steering wheel control module. Still everything peachy. Yesterday I replaced the LCD on the MFD and the surgery went fine (so nice to have a visible display!)


Since I had the instrument cluster out, I decided to hardwire my Valentine (V1) radar detector later in the evening. When I got home, I pulled the HU out. While I was at it, I also removed the factory CD changer and ran my USB, iPod and V1 wiring through the side hole and placed them where the CD changer used to reside. I also ran a microUSB cable. I spliced the wiring for the V1 and the microUSB to the same acc & ground wires for the head unit.


Once I put everything back together, no instrument cluster functionality. No lights, no display, no turn signal indicators and gauges are all at 0. What gives??? Everything else works (turn signals, high beams, door locks, flashers, rear shade, just no instrument cluster). I already checked the instrument cluster fuse (#42) and it's good.


Your help is greatly appreciated.

 

Probably blew the SAM. Search for that; I have no idea how to test for it directly, but that does seem to be the culprit for these kinds of conditions. And yes, of course it's expensive to replace.

Welcome to the fun world of modding Benzes. It's truly a love/hate thing, which is why my 02 C230 is now rusting in a landfill.

 

Thanks for your opinion, tommy. Not exactly what I wanted to hear, but you may be on to something.


I opened the center of the dash again a rechecked everything, moved my accessories to the wires on the cigarette lighter, reconnected the CD changer but still nothing.


I got my hands on a cheapie scanner and I'm getting P0600 code - "serial communication malfunction."


Any tips on checking what exactly this means? Can the disconnected CD changer be the culprit, or is the SAM still the main suspect?

 

I researched this yesterday over the internet, until I just couldn't keep my eyes open. Based on my findings, the from SAM is the primary suspect? If that turns out to be the case, can someone tell me from what Mercedes models and years I can acquire a replacement? I also found a DIY article with a link where to purchase a preprogrammed chip. Is this a worthwhile approach - has anyone done it this way?


For the time being, I left my battery disconnected overnight. Keeping my fingers crossed....

 

Okay, I found a reputable independent and they ran a diagnostic. They reset the ICU & problem solved. Seems I got lucky!