* Important – Please Read Before Calling *
We literally receive hundreds of phone calls per year on this issue.
Please note that UNLESS you are a service customer of AMC, live in the state of Maine, or are willing to transport your Mercedes here for service, WE CAN NOT answer questions about out-of-state vehicles and would refer you to the local Mercedes dealer in your state for assistance. If you are a current customer of AMC, or can transport your vehicle here, then we will do everything in our power to assist you with your issue, or properly handle any and all service work. Thank You!
Background
This Mercedes presented with multiple external lights out, or not working correctly.
Or the battery may be deeply discharged, or electrical accessories may not be working.
Location Is Everything
Locating the “SAM” under the coffee cup 
holder may not have been the best of design decisions.
Then again, Europeans don’t generally eat or drink in their cars.
Same with locating the SAM modules in the rear of the car, like the Mercedes ML320 and 350 vehicles, subject to water entry, not the best decision either. It worked, for a while, but leaking taillight seals, sunroof drains, or tailgate seals can really do a number. Water and electricity don’t mix well, it causes corrosion, and all kinds of electronic issues.
SAM stands for Signal Acquisition Module in the Mercedes world. A SAM module receives data from sensors, switches, and controllers, and can send data, actuate (activate) components, and monitor systems. Mercedes-Benz has been using SAM modules since the mid-90s. SAMs come in a number of shapes and sizes, depending on where they are located in the car. Some are part of the fusebox, some are separate modules, and most Mercedes usually have between four and five SAM units, depending on the complexity of the vehicle and systems.
Cool Technology
SAMs are very cool technology, replacing literally hundreds of discreet wires with a two or three-wire data network. They are usually super reliable and make your car more reliable…unless they get wet.
One of the top failures in the SAM control modules is water or in this case, liquid coffee damage, which leads to corrosion and eventual failure.
Typical Problems that cause SAM failure
Corrosion – It is possible that the SAM control module may have gotten wet, corroded, and eventually failed. Typically this is caused because the repair is performed near the SAM control unit. If the SAM modules are not closed and sealed properly, they will eventually corrode. If a SAM module fails due to corrosion, at first you may notice that electrical problems are intermittent.
Excessive Current Draw – SAM control units don’t fail often. Other than physical damage or corrosion, the next most likely cause to make your SAM unit fail is an excessive current draw. If you’ve done modifications to your Mercedes-Benz or have a module that is drawing too much current, that can damage your SAM unit.
Broken Wires – Broken wires or shorts can cause your SAM module to fail due to excessive current draw. We often see this with rodent damage or broken insulation.
Incorrect SAM Coding – If you just had your MB serviced and now you have a different problem, it is possible that there is a programming issue. During a repair, a technician may have reprogrammed a new sensor but didn’t complete all the needed programming. If this is your situation, it is important to read all fault codes before you start troubleshooting your Mercedes-Benz.
Correction
In the early model years, you could replace the SAM unit with a used SAM from another Mercedes-Benz and not worry about any programming. Newer Mercedes-Benz models require SAM module programming and the new SAM unit will need to be coded with the Sofware Calibration Number (SCN). You will need to replace it with a new one if you need a SAM. The new SAM module will need to be coded and programmed using the Star Diagnostic System (which we have at AMC) or the Mercedes XENTRY computer (which we also have) once it is installed.
The Proper Repair
The only true and permanent repair is to replace the SAM module and carry out programming, being certain that the cause of the failure, water entry, or other, is corrected. Pro Tip – If you don’t fix the original water entry issue, then the problem will repeat and reoccur, and you’ll have to do the entire repair process over again.
Value
At Atlantic Motorcar, we’re all about providing our customers with not only Great Service but also Value. We understand that “An ounce of prevention is worth a pound of cure.” (My mom would be proud I remembered that.) In other words, preventing or catching problems like these brake lines early can save you more than just money.
Finally
Questions, or if we can be of help in any way with service on your Audi, BMW, Mercedes, Mini Cooper or other European (and now Japanese) import, please contact us.
Our team of Service Specialists is here to help, for even the newest autos!
* Important – We literally receive hundreds of phone calls per year on this issue. Please note that UNLESS you are a service customer of AMC, live in the state of Maine, or are willing to transport your Mercedes here for service, WE CAN NOT answer questions about out-of-state vehicles and would refer you to the local Mercedes dealer in your state for assistance. (If you are out of state and still need to speak with us, and are from out of state, we are happy to work with you for a consultation fee, which can be paid on your credit card prior to the consult.) If you are a current customer of AMC, then we will do everything in our power to assist you with your issue, or properly handle any and all service work. Thank You! *
Don’t hesitate to call us today, at (207) 882-9969.
Knowing, not just “doing”, that’s the Atlantic Motorcar way.
Thanks!
Warmly,
The Atlantic Motorcar Center Service Team