This a GOOD one, for all the electrical and wiring GURUS
rear and front wipers were not working, checked fuses relays, i had to change circuit 15r relay and everything worked but the front wipers, took out both SAMS and they were in good CLEAN condition, since i had them out sprayed them with contact cleaner and put them back in, now here is where it gets tricky, check front relays for the wipers, they both have 12v on terminal 30 and on terminal 86, . 30 amp fuse (100) is good as well, when i checked the ground signal from the front SAM that activates the relays found out that the ground signal had 2.4 volts. no wonder why the circuit wasn't closing.i also checked the green and black cable that goes from front SAM to the relay box for continuity, the cable is good, if i test it disconnected from the sam. (pin 9 i think on the 40 pin connector to the fusebox), but if i plug it, it carries voltage.
now i am also assuming that the SAM activates the ground signal to wipers via a relay on the board i can hear it click once i activate the wipers,
now the questions are
could the front SAM be damaged?
could a rat have bitten a cable and now it has a short?
could some other positive cable be making contact with the ground cable and be shorting it?
could the ground signal that feeds the relay inside the SAM be corrupted?
could anyone provide a from sam complete schematics as well as pin out for every connector?
any advise or help would be really appreciated
Last edited by AARG; Jan 13, 2022 at 03:15 PM.
The wiper system is not activated by a ground, it is activated by turning on the stalk. Check ground W16/3. Pierce the cable with a thin pin and see there is ground.
Major, thank you for your reply and help, you are a big pillar to this community.
i checked the ground you suggested, it was good.
Fuses do come loose, if someone mistakenly put the wrong amp fuse or the wrong type or if you put the fuse in the wrong direction. My mechanic sent his son to help me, and the kid put standard fuses where they should’ve been mini, and they popped up. Sadly, I have learned that no one can really be trusted, to work on your vehicle.
I don’t believe a mechanic won’t remove a fuse for a different vehicle they are working on, and wait till you come back with complaints for the issue. Then they have a reason to charge you again. what it boils down to is having to learn a few things about my suv, so they don’t see me as prey when I book an appointment. I know my vehicle is suffering some serious issues, it has leaks for Mb’s sake, but how does a relay magically go missing, or any fuses for that matter.
I’d like a lock put on every fuse box, and a colored picture diagram in the inside cover, so I know exactly what fuse should be there and what color it should be. Why is this so hard? It’s Mercedes’, we spend thousands to own one, God forbid they should make some adjustments that provide simple, visible assistance.
And stop putting in features that continue to run once the key is removed. When I figure out how to rip the SOS teleaid and call crap out, I fully plan to do so. That stupid thing sounds like I have a built in fax machine inside my stereo.
Last edited by mastermercedes; Feb 8, 2023 at 09:51 AM.


