OK, needs some help, this is long but bear with me. I have a 2006 ML350. The other day the car started doing some wonky things. It started with the interior light coming on for a short period then off. Also, the computer was saying the rear hatch was open (it wasn’t), then flashing passenger rear door, then driver’s door…you get the idea. Then the doors would unlock from the key fob then not lock, then work again. Finally, on the way home from work the turn signals failed and the brake light (plus license plate lights) went out, in the dark! Finally, after I got it home, I set the alarm and after a few minutes it went off, I am assuming because it thought a door was open. I unlocked it but the alarm kept going. I had to disconnect the battery to shut it down.

So, I researched and landed on the rear Signal Acquisition Module (SAM) located under the rear fuse block as the possible culprit. Read a bunch of postings about it making the car behave strangely so thought I would look at it. Sure enough, there was a blocked drain plug and about an inch of water directly under the SAM. It has been raining hard here the last several days. I pulled the SAM out, cleaned up the water, blew the drain plug out and generally cleaned up everything in that area. There was a lot of moisture on the wraps around the various harnesses and I set a small electric heater fan to dry everything out.

Now, as for the SAM. These SAM unit run $500+ at the stealership and then you pay them more to “flash” (dealer only) your newly purchased unit. I watched a couple of YouTube videos on how to dry it out (if you shook it water drops flew out) and clean it up. Once I got the circuit board out, I gently dried it out with a hair drier. It was immediately apparent that the unit had some problems. There were dried white powdery deposits in numerous places on the board. I was able to clean up the board and, basically, make it look new again. I reinstalled the unit and it sorta kinda is working. All the functions are back except…still no brake lights, license plate lights, or turn signal lights. Everything else works as before. I have check (I think) all the possible fuses. Also, the turn signal lights flash when I lock and unlock the car or put the four-way flashers on but not at the turn signal lever. Obviously, at this point, the car is undrivable.

Sorry for the long diatribe but wanted to give full disclosure. Anyone have any idea how I should proceed? Thanks in advance for any and all help that can be provided, much appreciated.

 

Two options, you may have more that others will provide:

- have the dealer install and program a new SAM
- ditto for an independent M-B repair shop
- use the search feature on this site to read the voluminous quantity of information posted on this topic

 

I didn't buy the new SAM. I reinstalled the old one once I got it cleaned up and it seems to function with everything but I still don't have brake or turn signal lights. Are these controlled by the SAM?

 

Yes, the rear SAM controls the lamps you ask about. This is per WIS/ASRA, the Mercedes-Benz service, repair and parts documentation.

The options I listed above are to purchase a new SAM and have it installed and programmed, either at a dealer or independent shop.

 

You must replace the tail lamp seals or else the water entry will recur. Please read link below.

https://mbworld.org/forums/m-class-w...ml#post7352393

Explain exactly what is wrong with the signal light & brake lights? Do they flicker, completely dead, or what?