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A couple of question on the N10 Combination Relay

12K views 6 replies 3 participants last post by  SuperQuest 
#1 ·
I finally took possession of a 1995 S320 and now working through a few niggling issues. The major item is the lack of wiper, turn signal, or hazard. Research suggests that the N10 relay is the primary culprit.

I found a replacement relay, brand new but costs USD500.00! I noticed however that my part number has a [4] after the part number, but the replacement has not. What is the significance of this?

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Given the cost, I want to check a few things first.
I had a indie check the relay last weekend and we noticed that one of the pins in the bank of ~17 was burnt. Likewise, fuse #15 kept burning! Could the relay be the cause of this? Or might there be an electrical issue that needs investigation?

I will attempt to clean the relay tomorrow, before I consider purchasing that expensive part!




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#2 ·
I would disconnect the relay module on top of the fuse-box which actuates the wipers. The N10 sends the drive voltage to the wiper relay module.
Now understand their is a diode on the wiper motor, so I would check it, and try to power the motor to wiper mechanism just to see if the motor/diode is not shorted. I thing you need to unsolder the diode, and check the front to back ratio on it..

$500 is a lot to pay for a module, and in my country these modules used are $50, but if you get a used one. it must be the same year...

Check out my thread...

http://www.benzworld.org/forums/w140-s-class/2405689-mava-needs-help-wipers-95-coupe.html

Here is this one too

http://www.benzworld.org/forums/w140-s-class/1461153-windshield-wiper-relay-3.html

Martin
 
#3 ·
Thanks Martin. We actually disconnected the relay and the (intermittent?) wiper module on top of the fuse box, and tested the wiper itself by "hotwiring" it. We had to, as previously the wiper would work in position two, continuously and only when the turn signal was set to the right (but the blinkers didnt come on).

We tested several (intermittent) modules as well but issue remained the same. The thought from the electrician was that either the relay (due to the burn mark) or the combination switch might be at play. Unfortunately, the electrician is only familiar with w123/124/126's, so could not test the wiring connection fully.

Second hand relays were being offered at USD10 a pop, but none fit mine :(

PS: I read through your thread as well, so it does appear that the relay may be the issue.


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#4 ·
Additionally, would a problematic relay continually cause the fuse to blow? From what I am reading, its not typical. In fact, now I am thinking whether to clean the relay (want to avoid it if I can) first, or have an electrician test if there is a ground problem!
 
#5 ·
I have looked up the part number shown in your photo in my EPC, and it looks to me that it is not the correct N10 relay for your model.

My EPC shows relay 140 542 04 32 is for model 140.051. (500SEL, S500) and model 140.057. (600SEL, S600)

You have model 140.033. (S320 USA)

Your relay should be Part no. 140 820 26 26 up to chassis A290166, or 140 820 76 26 from chassis A290167.

So maybe you do not have an electrical fault here - just the wrong relay?
 

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#7 ·
So, I just replaced the #15 fuse, and for the first time, wiper position 2 and 3 works... and the radio turns on - only in those positions. The radio never turned on since getting the car. The turn signals/hazard remain dead.
What could this mean? The relay could still be the problem I reckon... or the combination switch.


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