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winecountryone 02-26-2010 02:18 PM

intermitent wiper control unit
My intermittent wipers worked up until 2 days ago.They quit "mid sweep" while running.I tried to trace the wiring but it disappeared into the harness.The other 2 speeds work fine.
FWIW the washers aren't working either.This is a 74 450SL.
I'm assuming the timer box quit working after 36 years.Where is it located and would a replacement have to come from a 107?
I thought the EPC might be of help but I am unable to access it.All 3 of us in the house use various flavors of Apple running OSX 10.4 which is NOT SUPPORTED by Mercedes Benz at this time.

meltedpanda 02-27-2010 09:11 AM

I thought the switch put the motor into intermitant mode?
I will try to pull up the epc to see what I can find

meltedpanda 02-27-2010 09:26 AM

PM sent

winecountryone 02-27-2010 11:11 PM

no timer box,nust be switch
Between the EPC diagram and a wiring harness diagram I found in an old manual at the local library today it seems there is no separate timer box.
I will try cleaning switch and report if successful.
Thanks Meltedpanda for your help!

Deltacom 02-28-2010 04:38 AM

There is no relay or box between the operation switch and the wiper motor. The timing and speed frequency is controlled by the impulse switch attached (soldered) onto the wiper motor and the motor needs to be removed to replace it. Part number A0008200610

There is a conclusive test that can be carried out to determine whether the operation switch (multifunction stalk) or the impulse switch are faulty.

1. Remove the plug connected to the wiper motor and put to one side. On the motor there is a male connector with 5 pins as per pic below. Refer to them as numbered as per photo.
2. Connect a wire to the 12v positive pole of the battery and connect to pin number 3 (with a croc clip) and a negative wire to pin number 6.
3. Connect and additional wire to the positive pole of the battery and hold it in turn briefly to pin number 2, then try number 4 and then number 5.

While there is power to pin number 3 and ground to pin 6 the motions of the motor when 12v is applied to the above pins will be: to pin number 2 is slow wiper motion, to pin 4 is fast and pin 5 is interval (intermitant). The impulse switch controls time and frequency. If the three operating modes are good when the above test is carried out then the faulty item will be the operating switch at the stalk multifunction control. If any of the three operating modes are not obtained then the impulse switch is faulty and needs replacing by unsoldering the faulty one and resoldering a new one in place. Hope this helps.

Impulse switch Part number A0008200610

winecountryone 02-28-2010 01:05 PM

That's a BIG help!
Printed this out and will perform tests as described.This is exactly the info I wanted.
Big thank you!!!

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