Rear window demister problem - C180

Praxxus

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Hi all !
I have a RHD (UK) C 180 1998 on which the demister in the rear screen doesnt seem to work.
I have checked the fuse in the engine compartment ( its OK ).
The grid on the screen is intact.
The connections to the grid are good.
Pushing the button on the dashboard center console doesn't light the red light, but the night illumination behind it does light.
The two other buttons below it light up the red kight when pushed and are functioning correctly ( EC, air recirculation) with night illumination.
I haven't changed the fuse, as it seems to be not burnt out.

Any help appreciated
 

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Hello and how are you. :D


The control unit in the dash, sends the signal to the output relay N10 in the fuse box, this is a latching device that in turn puts on the lamp in the control unit, to show that its working.

The fault could be either the control unit or the output N10 relay,, these boxes can get dry joints and worth checking and re soldering

119 in the link

http://www.detali.ru/cat/oem_mb2.as...417717.418&CT=F&cat=45H&SID=54&SGR=045&SGN=05
 
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I'm sorry, could you be slightly more specific as I thought relays (N10) were sealed units ?
Is the control unit the push button in the heater control area of the dash ?
 
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Or is it 'in the dash' ie behind the button some how ?
Will check the relay connections tomorrow when its light enough.
 

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It is possible to remove the cover from the N10 relay in the fuse box. The press button unit in the dash sends the signal to the Relay inside the N10
 
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Oh, ok got it !
Thanks for the quick reply !
 
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OK Ive taken the relay cover off what I think is N10.
There are 3 relays within it, 2 similar ones (blinkers & wiper) and 1 that doesn't seem to work
 
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Update !
If i manually press the contact in on the copper coloured relay, the engine revs drop, and if i breath on the rear windscreen lines appear, but the button light doesnt come on. Pushing the button still doesnt work. Is it a relay fault or a broken part some where ? The circuit board alongside the relays does have a dodgy looking part on it ( I do wish i could post a Photo of what Im talking about ! ). Eurocarparts do a relay for £51
 
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Me again !
Television, What do you reccommend that I do ? Can this be DIY fixed or will I have to buy a new relay ? Do you think the button is broken and can be fixed ?
I presume you do Mon - Fri on here so I'll post back Monday night !
 

television

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Me again !
Television, What do you reccommend that I do ? Can this be DIY fixed or will I have to buy a new relay ? Do you think the button is broken and can be fixed ?
I presume you do Mon - Fri on here so I'll post back Monday night !

First I would unclip the cover off the N10 and re solder the window relay. they are expensive things to buy and you do not know if the N10 or the control panel, it is very hard to test these thing as the dealers had or have break out boxes that plug into the relay socket, and the relay plugs into this, with this socket you can test and measure the pins. We have to do it the hard way by pushing pins through the plastic on the wires and joining onto those.
You could have someone pressing the button while you move the relay in its socket gently to see if it is a connection thing, as I said its self latching and the LED cant light until the signal comes back from the N10
 

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You could get an aerosol of non drying contact spay from Maplins and spray all of the fuse holders and contacts on the N10, do not forget that this circuit only works in Key2
 
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Praxxus

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Tried the wiggling the relay - no joy I'm afraid.
I've uploaded some piccys of the relay.
The thing I found that was looking dodgy is circled.
Sorry to be dumb, but what is 'key 2' ?
Could you put a name to this spray from Maplin's please ? As I have some silicon spray in the garage.
 

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television

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Silicon is an insulator and not so good as a switch cleaner, the one that Maplins is a non drying switch cleaner, they only do the one

If the joint is broken on your relay where you have marked it just re solder the joints so that they are bright and shiny applying solder as you go

The big relay is the heated window one,,are the contacts clean and is that well soldered

All of the fuses should be sprayed with a cleaner.

I will see what else I have
 
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Ok ta !
Thanks for your patience Malc.
I wll try Maplin tomorrow after work.
Many thanks again, for the help.
 
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Praxxus

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I found SERVISOL SUPER 10 on Maplin website, it looks to be the 1 to use.
 

television

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I found SERVISOL SUPER 10 on Maplin website, it looks to be the 1 to use.

Thats the one, so do all of the fuses and pins on the relay
 


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