‘96 S124 E320 relay clicking and radio on after key removed?

[coneybiller]

I’ve got an electrical gremlin in my car at the moment! Which is causing me to disconnect the battery when I get to work and when I get home and loosing all of my radio settings each time

When I switch the ignition off and remove the key, the head unit stays on, along with the cigarette lighter socket (I’ve got a phone cradle plugged in with a volt meter in it which stays illuminated). I’ve noticed also that all windows still work and the elec seats also still have power, even with the door open. If I then switch the front wiper on, everything else goes off and the wiper will barely move and causes a relay behind the fuse box to go crazy. The SRS light is also starting to come on. Everything functions perfectly when the engine is running.

Now my battery is pretty shot and I’m thinking of replacing this anyway due to it sitting between 10.5 and 11v without the engine running (I do 150miles a day in this car, so it gets plenty of charge!!) and ~14.4v with the engine running.

I feel like this could possibly be a relay issue, but not sure which relay does what! I removed what I believed to be the N10 relay(which I read feeds the wipers and some other things?) but the wiper still tried to move and it didn’t change the fault at all.
Or could this be down to low voltage, which is not energising a relay enough perhaps?

Arrow points to the relay I removed thinking it’s the N10 relay?

Any ideas?

Regards

Ben

 

[grober]

http://www.autolib.diakom.ru/CAR/Mercedes-Benz/1995/E320/SYSTEM WIRING DIAGRAMS/

Sounds like water in the electrics somewhere- possible under that relay/fuse unit where a lot of electrical wiring goes through the bulkhead- Look for signs of water ingress/ choked windscreen drain channels

 

[Gbrowncls55]

ignition switch failure?

 

[coneybiller]

http://www.autolib.diakom.ru/CAR/Mercedes-Benz/1995/E320/SYSTEM WIRING DIAGRAMS/

Sounds like water in the electrics somewhere- possible under that relay/fuse unit where a lot of electrical wiring goes through the bulkhead- Look for signs of water ingress/ choked windscreen drain channels

I had the scuttle panel/wiper motor off about a year ago to change the blower motor and noticed the lower windscreen seal doesn’t sit on the screen properly, nor does it even slot into the trim attached to the motor. But I’ve also had no issues up until now!
Is there anything I can check, to isolate which system is being affected as such? Or to give me a rough clue of where to start?

ignition switch failure?

This was another thought of mine, but the ignition goes off, no lights, no engine and it’ll be a pain in the ass to fix lol!

 

[grober]

GOOD START IS TO CHECK TTHE WATER DRAINS ARN'T CHOKED.
W124 Water Drain unblocking

60 Body Shell

 

[wrdcc01]

You did pull the right relay for the wipers. Without that in circuit there should be no connections at all to the wipers. It is being back fed either by a short in the relay socket and/or a back feed from the rear wiper circuit which is powering other circuits through the ignition switch. Try pulling wiper fuse and if the radio etc go off then it will confirm there is a fault towards the relay connections. If water has been upto no good then it could be a mess under there.

 

[coneybiller]

You did pull the right relay for the wipers. Without that in circuit there should be no connections at all to the wipers. It is being back fed either by a short in the relay socket and/or a back feed from the rear wiper circuit which is powering other circuits through the ignition switch. Try pulling wiper fuse and if the radio etc go off then it will confirm there is a fault towards the relay connections. If water has been upto no good then it could be a mess under there.

That is not what I want to hear! But it is what it is I suppose!
I’ve just replaced all of the fuses (apart from the 25a as no stock and I think they’re plastic bodied, but they’ll do for now until I can source some high quality versions). I’ve also put a brand new Bosch S5 battery on there at the same time. Fault is still there, but the old battery was tired any way so needed replacing.

I’m almost swaying towards the ignition switch, the barrel is fairly floppy, but you can hear a relay on the passengers side click off when switching it off, but as ever the radio/cig socket is still running and you can also hear the central locking/seat pump operating over and over, until you switch the wipers onto full speed, then everything goes off and stops working.

 

[coneybiller]

http://www.autolib.diakom.ru/CAR/Mercedes-Benz/1995/E320/SYSTEM WIRING DIAGRAMS/

Sounds like water in the electrics somewhere- possible under that relay/fuse unit where a lot of electrical wiring goes through the bulkhead- Look for signs of water ingress/ choked windscreen drain channels

And that is mega helpful, thanks for the link

 

[wrdcc01]

Did removing the wiper fuse stop power to the radio? This would prove the fault away from the ignition switch? Also check the rear access panel where the rear screen wash bottle is, the rear wiper controls connect to the front wipers here in a multiplug that may be wet from a leaking rear side window.

 

[coneybiller]

Did removing the wiper fuse stop power to the radio? This would prove the fault away from the ignition switch? Also check the rear access panel where the rear screen wash bottle is, the rear wiper controls connect to the front wipers here in a multiplug that may be wet from a leaking rear side window.

Ahh that’s a good one, the rear side windows certainly leak and fill up the wells behind the wheel arches.
I’ll check this also! The rear wiper I discovered today, also seems to try to work but cuts power to everything as well.
I’ll have another play with it this weekend and see if the relay when removed is still allowing the wipers to move.

Is the fuse box itself easy to remove?

 

[wrdcc01]

Very easy, 6 screws and the relay part lifts up although there is very little slack. If water has got in there then it will drain straight down the footwell carpet as it's an open box into the cabin. Have a quick feel around the accelerator. If you go to the link grober sent you and look at the power distribution diagram you can see how power being fed back into the circuits for the radio etc can also power up a few other things so pulling fuses one at a time and checking the radio should narrow down the problem.