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560 SEL 1988
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14 Posts
Discussion Starter #1 (Edited)
Hi to all,

I am new to this forum.
just bought a 1988 560 SEL with 160K miles on it.

Unfortunately this car does not have a clean maintenance record - only read
up on this list after we got it. so I am sure I will have to ask more questions
and find help here to try and keep it running.

I did try to find help to this question by searching this site. Could be my
fault to not succeed in finding information.

The combination switch works ok except for the timer setting of the windshield
wiper. Selecting the 'first position' seems to disconnect power to the wiper motor,
the wiper blades just stop wherever they are on the windshield. Only after
turning off the wiper do they return to their off position.

According to suggestions on this site I already got the manual CDs and
determined a smaller box with electronics and the 'timer' in it, located within
the fuse box - just infront of the driver under the hood. Acoustically one can
hear the timer relay switch at regular intervals when the first position is
selected with the combination switch.

I did not fully understand the electrical diagram, I guess electronic circuits in cars
work somewhat differently. However the circuit itself looks ok, no obviously
burned or corroded parts.

What would be a likely place for the failure - the combination switch, or the circuit
in the fuse box or the wiper motor itself? Is it complicated (for a non mechanic)
to get to the wiper motor? Are there any test to determine what's at fault?

Thanks very much for any help,

Anton
 

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Registered
560 SEL 1988
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14 Posts
Discussion Starter #2
windshield wiper timer

Hi,

sorry just noticed a mistake, it is a 560 SEL.
Also, the found similar threads do not address the question I have.
thanks
 

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Registered
1999 E55, 2001 E320, 1990 560 SEC, 2004 ML350, 2001 ML55, 1995 S500, 1998 SL500, 2010 E550 Sport zoo
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7,035 Posts
You might try a call

Harrison is about 2hrs out, but you might try a friendly AR call to Shuler AutoHaus in Fayetteville, decent people once they know our face.

On your project - in the long run they also might also be able to help ou with some used parts - they have several parts cars..

Worth a try..
 

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Registered
560 SEL 1988
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14 Posts
Discussion Starter #4
sorry to add to this another email.

I have been checking back regularly and also tried to find more help within
the different forums on this site, however without luck. does this indicate
that I am on my own on this wiper/timer issue?

also tried to determine what kind of gas mileage to expect from a 560 SEL.
however the answers I found vary alot. so, if driven (friendly) on a US freeway at
60-65mph, does 20 MPG sound reasonable?

thanks
 

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Registered
1982 280 se aut. ecc. - sold
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1,607 Posts
there should be some kind of relay on your wiper motor that is supposed to get your wipers in the off position. At least this was the case with my Italian cars (not exactly the most reliable electric components). If you are lucky only this relay could get replaced.

gr. J.
 

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w126
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1,535 Posts
If you're light footed 20mpg sounds reasonable. I drive my 420's easy and I get max 22mpg. On the combination switch, positions 2 and 3 bypass the wiper module. Position 1(intermittent) and the wash function(timed) go through the module. It looks like when in position 1 you should measure constant voltage at pins 14 and 15 at the module/socket. Pin 16(hard to read in the schematic) which feeds the motor should switch on/off. The problem could be a dirty relay contact or a bad solder joint inside the module .From reading other posts in the forum I'd say problems in various modules arise from bad solder joints.
 

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560 SEL 1988
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14 Posts
Discussion Starter #7 (Edited)
Thank you very much for your hints.

I will take the plastic cover off of the module in the fuse box and try to measure the voltage on pins 14-16. As I mentioned, I actually can hear the relay itself switch. I sure hope the problem is located out in that box since I fear having to look into the combination switch or to get to the wiper motor.

About the MPG. I do not have any real information about the past of this car and was wondering if I should take a look at the timing chain. but I guess from your answer that 20MPG actually sounds reasonable.

Thanks again for all the help and I will post what comes of it.

Anton
 

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Registered
560 SEL 1988
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14 Posts
Discussion Starter #8
it has been a while and life just got in the way ...
still trying to understand the wiper/timer problem and just
a few days ago it actually worked for some time all by itself.

it seems that a contact inside the combination switch is
bad - if one very carefully/softly touches the lever and plays
around some, one can manage to make it work.

has anyone tried to clean or open that combination switch?

Anton
 

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Registered
560 SEL 1988
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14 Posts
Discussion Starter #9
fixed problem

today we fixed the problem with the timed wiper position of the multi-purpose switch. all it took was about 10 minutes, a little careful disassembly and cleaning.

will try and give details here. first one needs to realize that all the functionality for the wiper is actually located inside the handle itself, that black piece of plastic which is turned and pushed up/down to operate the signal lights and the wiper. closer inspection suggests only one possible way in by removing the top, a small cap with signal light indicating arrows marked on it. just place for example 2 small knife blades in the groves at opposite sides and gently with increasing force push out away from the steering column - there are 2 plastic snaps under the cap on opposite sides (in our case they were on the sides the indicating arrows are pointing to). no need to mess with the steering column, all can be done with switch in situ.

the cap will come off and one will find a big spring and a plastic disc with a single contact. those are lose and the spring actually popped out - but it is obvious and simple to put the 2 back.

pushing the plastic handle down towards the steering column reveals a cylindrical switch with a white plastic cap. that plastic cap again has two snaps and can be removed with care by pulling on it and pushing a little the snaps at the same time.

at this point 2 cylinders, a smaller one stacked inside, are visible (made from g10 or some such greenish circuit board material). the outer one is fixed to the stem while the inner cylinder is rotated with the outside plastic handle via a small metal pin. there is a pattern of contact points between those 2 cylinders and rotating the inner one changes between different combinations. after taking the pin out and bending two metal contacts sticking out at the top carefully out of the way, just far enough, slip out the inner cylinder.

19 years of operation cause some build-up that is now easily cleaned from all the contacts on the inside of the remaining outer cylinder. the smaller, removed cylinder
makes electrical connections across from one side to the other in two places. the contacts are on small metal fins that stick/push out. in our case, the metal of the lower one had fatigued and needed to be bent to stick out more again.

putting all back together does not pose a challenge. small hint: rotate the inner cylinder with metal pin not to the 'off' state, rather set it to the its first position, just before slipping the outer plastic cover back up. this seems to be the easiest (maybe only) configuration to get the cover back on with the markings aligned correctly.


(sorry, but the white plastic cap just doesn't come out in the shots)

anton
 

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Premium Member
1990 SEC
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4,254 Posts
Good pictures.

Thanks for the information on how to fix the steering column stalk. :)
 

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1990 Mecedes-Benz 420SEL
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1,217 Posts
Anton, thanks for the update. This is useful info for us all. I would never have known you could get the end of the combi-switch off.

Regards,
Dave
 

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Always Remembered RIP
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46 Posts
Thanks empla for taking the time to write that up and take pics.
I was all set to order a wiper relay when I discovered pushing the combination switch in a certain direction restored the intermittent wiper function.
It's a nice feeling when things can be fixed easily. :)
 

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Registered
1984 MB 380 SE, 1989 560 SEC
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262 Posts
Bravo, Anton! Great DIY article. Mine needs some attention, but still works, but it is on the list and I'll do this cleanup first.

Thanks
Charlie
 

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Registered
1990 300E 265,000 miles, 2003 E320 59,000 miles
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3 Posts
Thanks so much for posting this. Haven't been looking forward to pulling the steering wheel and changing the switch. I tried it last night and so far looks to be a success. My wipers would come on randomly, especially when making a turn. The only problem I had was when I removed the end cap I broke off one of the tabs that locks it in place.:crybaby2: Super glue did the trick gueing the tab back on.:thumbsup: Thanks again!
 

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Premium Member
1986 420SEL/1995 E300D/4 BMW’s/2 Vanagon’s
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1,026 Posts
Nice fix!

As far as MPG, everyone has differing results odd as it may sound. I track my gas mileage religiously in my 420 SEL. I do a mix of city highway. Last 5 fillups were:

18
16
19
16
20 (Almost all Highway at 70-75MPH)

I keep up on my car's maintenance and I think I am getting about as good as I can with a 420. Supposedly, the 560 is slightly worse on MPG so you might expect 17 on the high. The window sticker says its 14 city/16 highway for the 560. I can't seem to find a window sticker for the 420, but my guess is 16/18.
 
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