Huge electric problem? Im confused.
Everything has been fine until today.. In the morning today i took a short drive for like 15 minues, as soon as putted the car in R the messages for Faulty lights on trailer was popping up, backlights, turn lights etc. BUT i didnt even have a trailer hanging after the car, so... and no other malfunction codes, only this..
..i went home, didnt think about it to much, was trying to start the car again after 5-6 hours, but then every lamp in the dashboard was just blinking and no messages in the screen was popping up, i tried a few times, nothing happened, when i turned the ignition all off the lamps still blinked and stopped when i removed the key from the ignition..
i decided to charge the battery wich i did after i disconnected it, charged for about 3 hours, connevted it back, bur t now its completley dead, only flashes in backlights 1 time and i can hear the window on drivers side doing a little move, this is when i turn ignition on, but every other stuff is black, even the rooflamps.
after this, i tried to put on the charger when battery was connected but no sign of electricity then..
any smart heads here that know this problem?




You disconnected the battery, recharged it and now the ignition is not responding.
> The main assumption here is your main $200 battery is as good as new after recharging it... I'd question that first before going any further. Measure the voltage under load or get battery tested at the local store.
> The next thing is when you reconnect power you're supposed to pop keylessGo button and use the key in ignition once.
> You can try to do another proper Reboot with AUX disconnected.
> Buy an OBDII scanner to read all active faults. Then reset faults created by marginal voltage operations.
Why NOT use flat batteries:
-- Low voltage fries electrical contacts with high currents to deliver power (P= U x I).
-- In MB parlance it browns the delicate circuit contacts combs deep inside SAM's.
-- Float your batteries to achieve low-R efficiency.
✌️
Last edited by CaliBenzDriver; Sep 13, 2022 at 05:43 PM.
You disconnected the battery, recharged it and now the ignition is not responding.
> The main assumption here is your main $200 battery is as good as new after recharging it... I'd question that first before going any further. Measure the voltage under load or get battery tested at the local store.
> The next thing is when you reconnect power you're supposed to pop keylessGo button and use the key in ignition once.
> You can try to do another proper Reboot with AUX disconnected.
> Buy an OBDII scanner to read all active faults. Then reset faults created by marginal voltage operations.
Why NOT use flat batteries:
-- Low voltage fries electrical contacts with high currents to deliver power (P= U x I).
-- In MB parlance it browns the delicate circuit contacts combs deep inside SAM's.
-- Float your batteries to achieve low-R efficiency.
✌️
tried with new battery now, everything is still dead, no lights, nothing..
Last edited by NorMBAlex; Sep 14, 2022 at 05:22 AM.




Obviously power is not reaching where it's supposed to... switching power is SAM's and prefuse job
> Check the battery connections and GND strap to chassis are ok. If you have an old $20 multimeter now is a good time to play with it.
(> FYI: do not leave your new battery connected without a float charger as you run the danger to get the new battery run down overnight).
> Any lights okay, we have no dashlights but then...
How about turn on headlights switch manually?
How about brakelights?
> Rain soaked: reach under front carpets on either side for sign of moisture...
> Do you have an AUX battery in the trunk or driver side dash?
> What happened last time time this car was driven and then after that... ?
After changing both batteries, starter and aux battery, it was still dead. I then checked every corner of the car, and in the trunk on left hand side where all the fuses are, there was a module, it was all wet, i opened it up and it was nearly full green of corrosion, i dried it and sprayed electric spray, then let the cables dry up, plugged it all together, voila, the car is good as new! Just needed to adjust everything after battery change.
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After changing both batteries, starter and aux battery, it was still dead. I then checked every corner of the car, and in the trunk on left hand side where all the fuses are, there was a module, it was all wet, i opened it up and it was nearly full green of corrosion, i dried it and sprayed electric spray, then let the cables dry up, plugged it all together, voila, the car is good as new! Just needed to adjust everything after battery change.
Do you have a picture of that left-hand side trunk fuse box?
Good job bringing back to life the green mystery module that was killing your car.
The Best of Mercedes & AMG




great the car is back on the road.

However, have you found the root cause? The issue was not the module, but water intrusion and if you do not fix it, get ready for another headache.
Check the trim around the trunk, it seems water is coming through the plastic pins, or a damaged seal




great the car is back on the road.

However, have you found the root cause? The issue was not the module, but water intrusion and if you do not fix it, get ready for another headache.
Check the trim around the trunk, it seems water is coming through the plastic pins, or a damaged seal
furthermore, the Rear-SAM on the righ side of trunk if it's what it is, may stay awake or wake-up peripherals to drain battery.
Both sides of R-SAM PCB can normally not be reached for proper cleaning...
However, given you know already how to clean electronic circuits... it may be possible to remove upper R-SAM cover that's attached with melted plastic posts.
That has good chances to improve the final outcome with a 100% problem cure.
🤞





Our car is aging...so pay attention to anything called rubber/seal/plastic and the like....which keep water out of the car interior or trunk or engine bay Front SAM.
Sunroof drain hose also need attention




