turn signals not working


New member
It hapenned to me one time. I removed the fuse block under the steering wheel and it was the wire going into the connector. I wiggled the wire while having the turn signal ON and it would buzz/work, on and off. If that can be of any help


'05 T1N 3500 - NorCalSprinterCampout
it took me almost 10 years of intermittent turn signals, occationally replacing the relay, to finally just replacing the fuse block on the steering column. Got it at EuropartsSD.
Totally fixed it , really wish I had done it sooner
Same here, I lived with it for 4 years. Slapping FuseBox 1 made the flashers work when cold. The intermittent wiper function failed recently. A swap of FB-1 resolved both issues. (and now I have a sorta-good spare FB1 onboard)
Special thanks to Vanski for helping with the long overdue install (and some fresh glow plugs).


New member
Well, it appears most ppl have problems with the fuse box,turn signal fuses, or associated connections, but their vehicles DO NOT behave like mine in the respect that they lose all functionality when they do. I have functioning turn signals with hazard light activation, so all I can assume, is this is caused by a problem with the MFS, multifuction switch. Does anyone see error with this logic or suspect another item to be bad? I have replaced relays in the off-chance that somehow this could cause this behavior, and it made no difference. Turn signals only activate with hazard light activation.

Thanks for the help.



New member
Any updates on this, Dave? My 2002 Freightliner is doing something similar. When my headlights are off, turn signals work normally. When headlights are on, the left arrow stays on, and left turn signals do not work, but right do. Hazards work at all times. From this and other threads, I’m guessing the culprit is the MFS, though I don’t have the wiper issues that some have suggested it could have with MFS isssues. I’ve replaced the relay and checked fuses. Any other ideas here before I replace the MFS?



New member
Yes, IM sorry for the slow reply. I figured it out shortly after posting but didnt come back and discuss, oops. It was a very dumb mistake by me. I had pulled an alternate fuse to use as a replacement for my D+ fuse that I blew out hooking too big of a load to it. I pulled the windshield wiper fuse, yes the wiper fuse, to use as my replacement D+ fuse. I think they are around 10 to 15A. All was good I thought until it rains. Somehow I didnt correlate this to the turn signals going out. Proabaly because it had happened with some time separation as the van sits for long periods as I build it. ANYwayyyy, the wiper and the turn signal circuits power up together somehow using the same fuses, IDK at all, makes no sense to me and I know German cars, BMW's namely, inside and out. Someone more knowledgeable on the Mercedes wizardry... witchcraft, not sure witch, behind that wiring business, maybe can comment.


Erratic Member
As was answered in 158wb's other thread, Fuse 6 on the steering column panel powers the wiper motor AND the Wiper/Turn Signal/Engine Start Control Module.
Now we know...

Since folks aren't also complaining about "doesn't start", i really do wonder what that module does for/with/to starting?



New member
Recently had an issue in my 03 dodge, sprayed card cleaner (probably not the best, but what I had with me and it seems to have fixed my problem.

Sent from my SM-G950U using Tapatalk

Aqua Puttana

Poly - Thread Finder

Since folks aren't also complaining about "doesn't start", i really do wonder what that module does for/with/to starting?

The FB #1 is a module in the truest sense. It is not a simple fuse block.

That said, in my opinion the labels in the schematics are often general or sometimes vague. The FB #1 may simply be passing current to the correct place(s). That actual contribution may not be very complex.

:2cents: vic

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