Intermittent failure of parts of dashboard with whirring sound W124

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ChristophK

Member
Joined
Oct 23, 2018
Messages
38
Location
England
Car
E220 Carbriolet L Reg
Hello,
May I please ask for advice. I have a 1993 W124 convertible which occasionally does odd things. Currently when I put the key into the ignition the dashboard comes to life and shows me all instruments. When I start the motor a kind of whirring sound seems to come from the right side of the dashboard and the temperature, oil, fuel and revs stop working. The tachometer and clock still work.
Initially I thought the noise came from the fan but switching fan off made no difference to the noise. The next time I am in the car same happens again. Before the motor is on and the noise starts all clusters working.
A member of this forum already kindly posted me a link how to remove the dashboard but I have not done that yet (slightly worried).
Any ideas what this sound could be that seems to be associated with the failure of part of the dashboard?
 
Christophk I would ask some one to turn on your key ,,while you listen in the area of the fuse box that sits under the bonet driver side . You have relays in the bottom of the rear fuse box .This could be where the noise is coming from .
 
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Thanks for the tip. It certainly is making a noise in the area. I have attached videos from when I get in all is normal. Second the noise comes on and the clusters stop working and from under the bonnet. Any suggestions where to go from here?
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Christophk I would ask some one to turn on your key ,,while you listen in the area of the fuse box that sits under the bonet driver side . You have relays in the bottom of the rear fuse box .This could be where the noise is coming from .
Thanjs. For tip. I have uploaded some video I took today as happened again. Any suggestions welcome how to fix it
 
Thanjs. For tip. I have uploaded some video I took today as happened again. Any suggestions welcome how to fix it
If you open and remove the lid of the fusebox , you will see six screws holding the top part of the fuse box ( onto which the cover fits ) - remove all six ( you may need to open the bonnet fully vertical ) and lift it away - this will expose the relays at the rear of the fusebox - try your test again and see if you can localise the noise to one particular relay .

If you note the part number , which will be on the relay , see if you can find one on eBay .
 
If you open and remove the lid of the fusebox , you will see six screws holding the top part of the fuse box ( onto which the cover fits ) - remove all six ( you may need to open the bonnet fully vertical ) and lift it away - this will expose the relays at the rear of the fusebox - try your test again and see if you can localise the noise to one particular relay .

If you note the part number , which will be on the relay , see if you can find one on eBay .
Thanks. Done it and it seems like it is 2018210047 which I can even feel vibrate. Would that make sense? Interestingly I noticed when I switch on indicator the noise stops
 
If you open and remove the lid of the fusebox , you will see six screws holding the top part of the fuse box ( onto which the cover fits ) - remove all six ( you may need to open the bonnet fully vertical ) and lift it away - this will expose the relays at the rear of the fusebox - try your test again and see if you can localise the noise to one particular relay .

If you note the part number , which will be on the relay , see if you can find one on eBay .
Taken the unit out and went for a drive. The buzzing certainly has not come back and indicators not working as expected as unit taken out. But the dashboard started fine and then stopped working again....at least the noise is gone. Any idea what else could influence the display? I have ordered new used unit so noise will be gone hopefully
 
The other one which is worth checking is the overvoltage protection relay ( OVP ) , this is often over beside the battery and is recognisable as the one with the fuse on top .

It is basically a unit with a Zener diode , designed to clamp voltage spikes . This could be the problem as they can cause all sorts of odd faults when they fail .

Yes , the other one is the flasher relay .
 
At the back of your fuse box there will also be a big , long relay , usually starts with 126 or 129 . This is the bulb monitoring relay .
 
The other one which is worth checking is the overvoltage protection relay ( OVP ) , this is often over beside the battery and is recognisable as the one with the fuse on top .

It is basically a unit with a Zener diode , designed to clamp voltage spikes . This could be the problem as they can cause all sorts of odd faults when they fail .

Yes , the other one is the flasher relay .
I changed the ovp a couple of months back as abs light went on and off which fixed it. Hope not broken again. I will wait until new relay is here, hopefully by Saturday or Monday and I give it a go. Thanks for everyone's help. Enjoy this lovely spring evening.
 
Got the new relay and was putting it in full of hope but to be honest it is worse then before. While the old relay made a noise straight away and stopped when I indicated. The new one does not let me indicate unless I apply pressure and then it makes a noise too and the left part of the instruments don't work with either. Perhaps not the relay but something going to it?
 
Good news. I had another look today put the original in which still made the sound. Then I checked fuses again and they looked good but old and replaced them and voilà it works again. 😀
 
Hi there everyone! Could someone help me woth my matter. I just purchased a cla 66 plate 200 d, automatic and has a strange problem. They recon tgat the car been in the garage and the auxiliary battery whent off and now the sat nav is not working, road sign assistant as well. Would i be able to buy a new sat nav and just replace with mine or it will be more than that?
 
Hi there everyone! Could someone help me woth my matter. I just purchased a cla 66 plate 200 d, automatic and has a strange problem. They recon tgat the car been in the garage and the auxiliary battery whent off and now the sat nav is not working, road sign assistant as well. Would i be able to buy a new sat nav and just replace with mine or it will be more than that?
I am sorry I can't help. It might be worth posting it in a different forum as this one was for the older w124 and you might find people who know more about the newer Mercedes.
 

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