Front SAM
Thread Starter
Junior Member
Joined: Aug 2005
Posts: 41
Likes: 1
Front SAM
Please advise. My 2011 E63 AMG with VIN last 8 digit BA428200 has a front SAM with part number 2129005011. When I checked with Mercedes Parts Center the latest part number corresponding to the year, model and VIN of my car is now 2319007707. The parts center included a complete list of replaced SAM modules. I observed that my part number 2129005011 is not included in this list. Does this mean that the part that is installed in my car is a wrong part? I am addressing this because I have a issue with my electric cooling fan running for no reason even when engine is cold. Hoping some experts reads this request. Thank you in advance.
Super Member
Joined: Sep 2011
Posts: 878
Likes: 638
poop
I doubt a bad Sam would only have one symptom.
you need a scan for errors with xentry and I bet you'll find the fault. Likely a short in a temp sensor etcThere are a lot of different and updated part numbers for modules, I wouldn't get stuck on that
you need a scan for errors with xentry and I bet you'll find the fault. Likely a short in a temp sensor etcThere are a lot of different and updated part numbers for modules, I wouldn't get stuck on that
Thread Starter
Junior Member
Joined: Aug 2005
Posts: 41
Likes: 1
Front SAM
I went to MBEPC website. Furnished my VIN and I typed the part number of the SAM that is installed in my car 2129005011. The message came back UNKOWN. Maybe this SAM does not belong to my car?
Thread Starter
Junior Member
Joined: Aug 2005
Posts: 41
Likes: 1
Additional question diagnosing my cooling fan running even when engine is cold. There are four wires that connects to M4/7 plug that plugs into the cooling fan control module. One BN wire (ground), one RED wire (F32 constant 12V), one BKRD (From Front SAM) and GNBU (from ECU). When I disconnect the GNBU wire from the plug M4/7, the electric cooling fan still continue to run. However, when the BKRD wire is disconnected and the GNBU wire is reconnected the electric cooling fan stops running. Conclusion, is the Front SAM defective? Will appreciate your comments. Thank you
the BKRD is 12v ignition from sam only, the GNBU is signal from ECU, your fan is faulty or in second place your ecu is faulty which i doubt, change your fan.
edit: do you have fault codes in ecu like coolant temperature sensor or other related sensors that makes the ecu send signal to turn on the fan for safety?
edit: do you have fault codes in ecu like coolant temperature sensor or other related sensors that makes the ecu send signal to turn on the fan for safety?
Last edited by Robert AMG; Nov 23, 2021 at 05:50 PM.
Trending Topics
Thread Starter
Junior Member
Joined: Aug 2005
Posts: 41
Likes: 1
the BKRD is 12v ignition from sam only, the GNBU is signal from ECU, your fan is faulty or in second place your ecu is faulty which i doubt, change your fan.
edit: do you have fault codes in ecu like coolant temperature sensor or other related sensors that makes the ecu send signal to turn on the fan for safety?
edit: do you have fault codes in ecu like coolant temperature sensor or other related sensors that makes the ecu send signal to turn on the fan for safety?
MB World Stories
The Best of Mercedes & AMG
8 Oddball Mercedes Ideas That Actually Made it to Production
Verdad Gallardo
Dubai Tuner Gives the Mercedes G-Class An Entirely New Look
Verdad Gallardo
Six Gift Ideas Your AMG Loving Dad or Grad Will Cherish
7 Craziest Things AMG Gas Ever Built
Verdad Gallardo
New Electric Mercedes-AMG GT 4-Door Coupe Unveiled: 10 Things You Need to Know
Verdad Gallardo
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)
Verdad Gallardo
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Out Of Control!!
Joined: Apr 2019
Posts: 12,230
Likes: 6,903
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
variable rpm smart fan
Thank you for your response. I have replaced the cooling fan with a brand new one and it still runs as soon as it is plugged in. There are no trouble codes or CEL. Why is it when the ignition wire (BKRD) is disconnected the fan stops running. But if the GNBU is disconnected while the BKRD is connected the fan runs. So the fan keeps running when the BKRD is connected even when the ignition switch if OFF. Completely a mystery for me. Thank you.
Super radiator Fan :
This engine fan is built for variable speeds controlled from slow all the way to supersonic.
The 100Amp power is translated in the need for a direct connection to the PreFuse main supply.
To put the fan logic to sleep, a gated ignition signal is toggled by the F-SAM.
The fan speed is remotely controlled by the ECU and communicated through a PWM signal.
Where this legacy design gets twisted is with the PWM duty cycle law:
- 0% duty for failsafe > Max speed!
- 10% duty is fan stopped.
- 100% duty is Max rpm
Overall it is somewhat confusing the first time you get introduced to various causes of Max fan speed:
- bad A/C pressure
- missing ECU PWM
- genuine Hi-Temp 100% cooling
Conditions that stop the fan :
- 10% PWM duty cycle from ECU
- Ignition off with delay from F-SAM
- (bad prefuse link, GND etc)
Smart Temp Gauge...:
While in the cooling Dpt, don't trust the InstCluster temp gauge, it's computer filtered to conceal the thermostat variable temperature setting, also computer controlled. The gauge purposely translates all that for a user friendly idiot-display.
F-SAM is ECU's butler:
My best tip to make friend with your "sleepless SAM'S" is to power cycle your battery bi-monthly. This will effectively reboot all your 40+ computers all at once.
Hope this helps with a happy Thanksgivings 🦃
Last edited by CaliBenzDriver; Nov 25, 2021 at 02:30 PM.
Out Of Control!!
Joined: Apr 2019
Posts: 12,230
Likes: 6,903
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Have a look at live data with a scanner.
You may want to unplug power to your fan if you think it's safe temperature wise such as Winter in Canada.
