'96 S124 Indicators, Hazards & rear screen demist suddenly inoperative

[Ben's Mercedes]

Just as the heading describes really.

When last driven 2 days ago the indicators worked fine. I'm presuming the hazards and rear demist were fine too, though I didn't have a need for them at the time so neither were used/tested then.

On a short journey this afternoon I have found the indicators not working. Also, that when needing to demist the rear screen the switch wasn't opeative - it could be held in the on position and the "working" lamp in the switch illuminated, but the switch didn't latch/function when released and just returned to the off position/indication.

When running through the other switches to check for other fails, the hazard lights were also found not to be operating.

My immediate thought is a failing/faulty N10 relay and I will be checking this the best I can later, but quickly on-the-spot I checked/rotated the 6 and 10 fuses identified as on those circuits, and all seemed in order. But in the monsoon and failing light I wasn't inclined to whip the bonnet to vertical to get at the relays and begin pulling increasingly wet components!

In the meantime would the relay be the majority opinion? If anyone has thoughts about other potential causes however, I'd welcome hearing them in case I need to do some fault-chasing in other directions?

 

[bembo449]

do these have trouble with water ingress into the SAM units , assuming they have them ?

 

[DREAMER NO2]

W124 i think they dont have a SAM .Well the SAM is vacant in my W124 . Yes N10 flasher relay for sure when you have no indecators or hazard flashers .As for rear screen heater ,pull the switch out and open it up , on one i did it had just fell apart inside the spring had sliped off .
> http://www.w124performance.com/service/Main.html < some things might help in the free manual .

 

[Ben's Mercedes]

do these have trouble with water ingress into the SAM units , assuming they have them ?

Not typically, other than when you are trying an emergency fault-find in pouring rain!

But seriously, no the fuses and relays are well-housed in separate and separate-lidded compartments of a dedicated housing (photo, not mine, from a thread on relay failure), and the covers' closures create effective barriers to water ingress.

 

[Ben's Mercedes]

W124 i think they dont have a SAM .Well the SAM is vacant in my W124 . Yes N10 flasher relay for sure when you have no indecators or hazard flashers .As for rear screen heater ,pull the switch out and open it up , on one i did it had just fell apart inside the spring had sliped off .
> http://www.w124performance.com/service/Main.html < some things might help in the free manual .

Sounds good, thanks. I'm not sure I know enough to recognise a repairable fault if I open it up, but I might take a look though I am not all that handy with a soldering iron. Not sure how else to test it anyway other than the wiggle-test and a pin-clean.

I'm elsewhere today and not in the 124 for obvious reasons, but will be exploring tomorrow afternoon so thanks for the switch suggestion too and the link to the service manual - appreciated.