Rear wiper won't park

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Sun, 13/03/2011 - 21:08
Simon666
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Hi advice please so I can sort a niggling problem out

My 85 300gd will not park it's rear wiper. This happened after a partial rewire needed after some of the wiring melted. To cut a long story short the garage think the G was moved with the wiring loom loose as the rear door had been removed. As the wiper motor has a permanent live they think this shorted causing the wiring to melt.

The car is now back in one piece - complete with rear door internal wiring kit - and the wiring sorted. However the rear wipe will not park. And it wipes continuously even on intermitant.

The garage think that the 'park' bit of the motor assembly might have burnt out - they are not the ones who caused the melted wiring by the way - but would that affect the intermitant problem which I thought was controlled by the dash switch and does the motor have a park bit to burn out?

Any ideas so I can get it sorted in one visit

Many thanks for any advice

Simon

Ps. Ref heated rear window. If the dash switch does not light, does that mean the element will not work - no mist yet to test it the old fashioned way

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Mon, 14/03/2011 - 13:28
#1
Pistonhead
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Re: Rear wiper won't park

There are two thick black wires that feed the rear tailgate. One feeds the rear heated screen element, the second feeds the wiper motor, are these confused? The rear wiper switch contains the intermittent wiper operation. I am sorry that the electrical wiring diagram cover only models up to 1984.

You can get you information from the Mercedeses website, address given below. Register on to the site and subscribe to use the workshop information system “WIS” (pronounced WHIZ). It will cost € 4.00 for an hours use.

www.service-and-parts.net

Cheers,

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Mon, 14/03/2011 - 13:35
#2
mgrays
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Re: Rear wiper won't park

For a parking windscreen wiper... you have 3 wires going into it.
1. Earth
2. Permanent Live
3. Switched Live - by relay if intermittent or direct if no intermittent

The "park" happens because the motor output shaft has a copper track around it with a contact. This circular flat track has a break in it where the motor stops and hence arm parks.

So check the 3 wires .. if it is not parking then pull motor apart as the "break" in the copper track is no longer there/filled with conductive material.

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Mon, 14/03/2011 - 20:58
#3
Simon666
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Re: Rear wiper won't park

Thanks both of you for the info.

Looks like a good place to start is an inpection of the copper strip. I am prety sure it is wired to the right supply as it only works using the correct dash switch. It ended up in the body shop for a good few months so perhaps all the messing about meant the channel just got filled in... That or the intermitant bit of the switch is frazzled as a result of the short.

Ta

Simon

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