Hi all, Need some help please.
Battery died after lights were on for 8 hrs.. Jumped battery. Car started. Horn wasn’t working, blinkers, wipers, mirror adjustments, radio, and my FOB wasn’t working. Trunk was opening by itself, moonroof opened by itself and it wouldn’t close. Got home and disconnected the battery. Connected it after 15 minutes and the blinkers, radio, FOB, and moonroof are working again. wipers and mirror adjustments and horn still not working. Dashboard showing messages that I attached. Any help will be appreciated. Thank you
Edit: Brakes were serviced end of August
Thank you for reaching out to us regarding the electrical issues you’ve experienced on your car post a battery drain. It’s crucial to address such problems promptly to avoid any inconvenience or potential damage to the vehicle’s electrical system.
Battery Check:
The first step would be to ensure that your battery is in good health. A drained battery can cause numerous electrical malfunctions. We recommend either fully charging your existing battery or replacing it with a new one to ensure adequate power supply to your vehicle’s electrical systems.
Front Signal Acquisition Module (SAM) Check:
Your Mercedes is equipped with a Front Signal Acquisition Module (SAM), which serves as a centralized control for your car’s electrical systems. If the battery issue did not resolve the electrical malfunctions, there could be a problem with the Front SAM. It’s responsible for processing signals from various sensors and controlling several functionalities like lighting, wipers, and the horn. A malfunctioning Front SAM could cause the issues you have described.
Diagnostic Scan:
If the above steps don’t resolve the issue, a diagnostic scan is necessary. Our YOUCANIC full system scanner can be very helpful in this situation. It will scan your vehicle for any fault codes and help identify any underlying issues that may be causing these malfunctions.
Thank you for the quick reply. I hooked up the trickle charger last night, battery was at 75%. Connected it this morning at 100%. No changes to my issues unfortunately. Does the SAM also deal with my windshield wipers? Wiper motor was replaced a little over a year ago. Should I check for blown fuses and relays first?
Yes, it does control the wiper as well. You can check relays, but water or even moisture got inside that SAM it is damaged and it may be difficult to tell just by looking at it. They do tend to go bad quite frequently. Get a front SAM that has the same part number and you should not need to do any programming.
I checked the fuses in front SAM yesterday, about half of them lit up the other half weren’t lighting up. I pulled the ones that weren’t lighting up and there were no cracks in them. So, i’m assuming the SAM is bad…
The SAM unit is a main suspect here. Pull the old unit out and find a used SAM but try to match the part number and ideally if you can the software number which is right below the part number.