W124 intermittent wipers (again)

[crt]

I know variants of this have been done to death but I am now stuck.

Problem: wipers on my '95 E300D come on intermittently.

Solution: take out big N10 relay, clean contacts on relay and in fuse box (and for good measure everything else in sight) with electrical contact cleaner. Replace.

Result: wipers still come on intermittently. Live with problem for months.

Latest development: wipers come on more frequently just as glow plug warning light starts coming on. Automerc replace N10 relay with brand new Mercedes item (v expensive) while changing glowplugs (one had failed).

Result: intermittent wipers on ALL the time.

Solution: take out new relay, clean everything with contact cleaner and replace.

Result: No difference.

Solution: Put back in old relay.

Result: Wipers back to an acceptable level of intermittent operation (i.e., sporadic, not all the time).

Any one have any bright ideas or suggestions? I have read that driving with a faulty glowplug can cause relay problems. Could the two things be connected?

Thanks.

CRT

 

[sixpack]

wipers

Hi CRT,

Different car but probably same fault. C250 (202), caused by partly conductive dirty grease inside the wiper stalk. You can clean it by taking the cap off the end of the stalk and squishing it with switch cleaner. Watch the spring inside as the cap comes off. The real root of this problem is the design of the relay circuit that the stalk switch feeds. The input resistance is higher than it need be so is quite sensitive to leakage. I added a resistor to earth to soak up the leakage, (10K I think), but later just cleaned the switch. I posted this answer to another member recently, He had a problem getting the cap off. I recommended a blunt knife into the join. I dont think the glow problem is related, just one of the glow plugs failed. Dont do what I did and break the plug off at the thread. This was on a 5cyl. 605 engine and it started ok through the winter on 4 but was a bit rough for the first 15 secs.

Peter

 

[television]

Sixpack has put a good answer and cure, I have heard of this and I hope that it works,it should

 

[crt]

Thanks for the suggestion. I will give it a try and report back.

 

[FIBAMAN]

six pack has good solution, but make sure you use a good contact / electrical cleaner which will evaporate, do not use wd 40 or similar. If you have had this problem for a little while there can be a minute track on surfaces of the assembly, wd 40 can wash dirt particles into the track and actually improve conductivity.

 

[Bolide]

In my experience intermittent intermittent wipers are caused by a faulty multifunction switch more often than by a bad N10

Nick Froome
www.w124.co.uk

 

[television]

In my experience intermittent intermittent wipers are caused by a faulty multifunction switch more often than by a bad N10

Nick Froome
www.w124.co.uk

Thank you nick,thats worth knowing

 

[crt]

Right. Popped the end off with a table knife catching the spring in the process, gave everything a thorough squirt with cleaner and then put it all back together to find that one of the two small securing lugs on the side of the cap had broken off so it won't snap back into place.

Anyway, when securely assembled (with tape for now), I still get intermittent wipers. So, I took it all apart again a few times, and on one occasion accidentally missed out the small circular sprung contact which sits within the big spring and which I have concluded is used to make the circuit to operate the washer/wiper function. Now, without that little sprung contact I had no intermittent wipers. Of course I didn't have the wash/wipe function either but I did have the normal wipe functions in the three twist positions.

This has got me thinking that the fault may lie with the small circular contact and the way in which it sits inside the m/f stalk and perhaps it might be making intermittent contact with one or both of the two corresponding contacts inside the stalk and so is operating the wiper. If so, perhaps I can massage either the circular contact or the corresponding contacts to prevent the circuit being made until the end cap is firmly pressed.

Before I start tinkering anyone have any views about this theory and, if plausible, any tips as to how best to execute a fix while minmising the risk of costly damage?

Thanks.

 

[crt]

In fact, the circular contact and corresponding contacts make the circuit for the washer, so it must be another part of the end cap/spring combination that makes and breaks the circuit for the wiper in conjunction with the washers.

 

[television]

Its too hard to comment without seeing it,, at least it shows that it was the switch at fault

 

[sixpack]

Wipers etc.

Hi CRT, looks like your getting near to the answer. Your right I forgot about the wee washer that works the wash/wipe. Did you get much dirty grease out?. Mine was really grotty. I used a switch cleaner called "servisol", well known in the radio trade. Its a good solvent but leaves a little lubricant behind. What did you use? To prove the fault you could measure the resistance at the connector lower down on the steering column. Its a bit fiddly but thats what I did, I think it read about 20/30K. I assume you know about meters and things with name like CRT, or are they your Initials !

Peter

 

[crt]

With so many flat screens around not many people think of crts anymore.

I don't have my multimeter with me so won't be able to check the resistance this weekend, but when I get it, from where to where am I taking the measurement?

The electrical contact cleaner I'm using is one from a general motor factor, not servisol though. The contacts were not very grungy at all.

I will have another poke around in the morning and see where I get to.

 

[crt]

Fingers crossed it seems to be fixed following the dismantling and cleaning operation of the m/f stalk switch recommended above. However, on reassembly, if the end cap, with sprung contact insert, was fully pressed home it triggered the intermittment wipe but as the locating lug is now broken it was easy enough to tape the end cap into place just short of a tight fit. Now to work out how to reattach the end cap in a more permanent and tidy fashion.