Wipers not parking!

[adam928]

Hi guys!
Well, the wipers on my '83s have never parked. They stop wherever they happen to be when you switch them off at the stalk!
I've changed the relay with a new unit from Porsche, and the motor with a working second hand item. Still doesn't park!
I assume there is some electrical gremlin somewhere, but don't know which wires to test?!
Anyone got any advice where to start?
Cheers, adam!


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[stepson]

I always thought the relay caused the wipers to park.

[adam928]

So did I, but when that didn't work, I was told the motor could be at fault?!


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[JK McDonald]

The 928's multiple speed select, on/off switch, adjustable delay-relay operation and the cam operated park switch inside the wiper motor can be broken down to the simplified circuit below. Here is a very basic 2 speed schematic shown in the stopped - parked position. Notice that the primary wiper switch is a two part mechanical (dotted line) movement that controls power to the motor speed select contact (top portion) and the parking brake/ground (lower left) for the wiper motor park cam. The internal park cam switch constantly bumps it's center contact to an up and then down position with each rotation of the motor/sweep of the wipers.

When the primary wiper switch is moved up (low/high speed in this example) power is applied to the motor - the lower left portion of primary switch is open and ignores the cam switch movement. With both cam switch contacts (53a/31b) now open, even though it's center arm has power coming down from the (low/high) speed switch - it has no affect as the wipers are sweeping.

Once the primary wiper switch is moved to OFF (As Drawn) the park circuit is now activated. The lower (off position) contact of the primary switch now provides power down to the upper contact of the cam switch. If the wipers are still high on the windshield the 53a contact will be closed and directing an alternate power source to the top of the wiper motor. As the cam rotates and the wipers reach the park position - the cam switch moves to the position as shown and everything stops. The ground (lower left portion of the primary switch) now applied to the top of the motor helps to quickly disperse/dissipate any collapsing magnetic flux within the motor windings to brake or stop any armature coasting past the park position.

http://www.speedyjim.net/schem/wiper2.gif

Looking at the wiring diagram for your car I suspect that the +12 volt power source (wiper selected to OFF) down to the wiper motor 53 (green/black wire) contact is missing. This source loops through the washer switch portion of the windshield wiper control switch. Perhaps if you wiggle the control stalk a little as you select park will tell you something ........

Good Luck, Michael

[5l32v4c]

Did you see what happened to Jeremy Clarkson's wipers on the Top Gear Patagonia Special? Shock absorber came right through the top of the shock tower and pierced the wiring harness.

I had the issue you described here on a different and it was the contacts in the wiper housing.

[adam928]

Originally Posted by JK McDonald

The 928's multiple speed select, on/off switch, adjustable delay-relay operation and the cam operated park switch inside the wiper motor can be broken down to the simplified circuit below. Here is a very basic 2 speed schematic shown in the stopped - parked position. Notice that the primary wiper switch is a two part mechanical (dotted line) movement that controls power to the motor speed select contact (top portion) and the parking brake/ground (lower left) for the wiper motor park cam. The internal park cam switch constantly bumps it's center contact to an up and then down position with each rotation of the motor/sweep of the wipers.

When the primary wiper switch is moved up (low/high speed in this example) power is applied to the motor - the lower left portion of primary switch is open and ignores the cam switch movement. With both cam switch contacts (53a/31b) now open, even though it's center arm has power coming down from the (low/high) speed switch - it has no affect as the wipers are sweeping.

Once the primary wiper switch is moved to OFF (As Drawn) the park circuit is now activated. The lower (off position) contact of the primary switch now provides power down to the upper contact of the cam switch. If the wipers are still high on the windshield the 53a contact will be closed and directing an alternate power source to the top of the wiper motor. As the cam rotates and the wipers reach the park position - the cam switch moves to the position as shown and everything stops. The ground (lower left portion of the primary switch) now applied to the top of the motor helps to quickly disperse/dissipate any collapsing magnetic flux within the motor windings to brake or stop any armature coasting past the park position.

http://www.speedyjim.net/schem/wiper2.gif

Looking at the wiring diagram for your car I suspect that the +12 volt power source (wiper selected to OFF) down to the wiper motor 53 (green/black wire) contact is missing. This source loops through the washer switch portion of the windshield wiper control switch. Perhaps if you wiggle the control stalk a little as you select park will tell you something ........

So if I apply a 12v source to the green/black wire, and the wipers park, then that would suggest a break in that power source somewhere, or am I misunderstanding something?!

Thanks for all this information, it really is appreciated!

Adam

Good Luck, Michael

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[JK McDonald]

Hey Adam, Without a matching wiring schematic on your end it will be a little difficult to do any serious wire chasing but I'll try to help. Since you have already changed out the interval (delay) relay and the wiper motor (both potentially the reason for your problem) we'll assume the No/Park issue is elsewhere.

1st let's set up the circuit status -

1) The windshield wiper (WSW) stalk switch is in the OFF position - Assume that the wipers were running and still positioned in the middle of the windshield.

2) Fuse 16 provides +12 volts to C1 terminal of fuse panel and on to (Black/Green wire) the now open WSW stalk Switch contacts - (The WSW switch is actually made up of multiple sets of contacts that open,close and are spring loaded to work in unison) -

3) From the C1 terminal +12 volts is also directed (Same Black/Green wire) to the still CLOSED WSW cam switch inside the wiper motor (wipers not in park position -refer to simplified circuit above) -

4) +12 volts leaves closed cam switch (Green/Blue wire) to terminal C8 of fuse panel and into (pin 53s) and out (pin53m) of the deenergized contacts inside the interval (delay) relay.

5) +12 volts continues to C2 terminal of fuse panel and then to (Solid Green wire) terminal 53e of WSW control stalk switch (This is in the Push/Pull washer portion of the stalk switch)

6) +12 now goes on through a (off position but closed portion of the stalk switch) closed contact of WSW switch (stalk in off position) and out on terminal 53 (green/black wire) -

7) This +12 volt source (green/black wire) is completed and provides power into the WSW motor which rotates until the cam switch opens in the park position.

The copper fingers that make up these multiple sections and contacts inside the windshield wiper switch assembly have a tendency to distort or become dirty just enough to not close properly. Sometimes you can clean the contacts by running a piece of paper (alcohol and torn match book cover) between the contacts to remove the contamination.

One other point that may also help and to answer your question about applying power to force the WSW motor to park - If you jumper the +12 coming out of the WSW motor cam switch (Green/Blue wire) to terminal 53 of the motor and it now parks you have eliminated the wiring, delay relay/washer switch contacts, etc.... Be very careful working around the wiper linkage - it is powerful enough to take off any protrusion that gets in it's way.......

Keep Us Posted and Good Luck, Michael

[honerboys]

I found this thread while searching for a solution to my problem - my wipers will not shut off - as soon as the key is turned to on position they start - they seem to be operating at the slowest speed - the stalk switch when moved up will make the wipers speed up - on the intermittent setting they still operate at slow speed not intermittent - so does the intermittent relay park the wipers and could a bad one cause my problem? - I removed the relay and it had no effect still operated as above - I disconnected the green/blue wire from the motor harness plug and it had no effect - I was thinking if the park contact in the motor was stuck closed the motor would continuously hunt for park - disconnecting that wire (I think) would remove the 12v that the motor needs to do that - is my thinking on this correct? - just hoping some one else had this problem and it was a relay before I tear into the motor - thanks

[stepson]

I am not an electrical guru by any stretch of the imagination, but if you removed the relay and it still happens, then it must not be the relay.

You have something else going on. Your theory on it's cause makes sense to me, but maybe one of the electrical gurus will jump on.

[honerboys]

stepson - I hooked up a spare wiper assembly and it did the same thing so I assumed I wouldn't have two of those with the same problem - I then removed and opened up the relay and the contacts were fused together - I "sawed" them apart with a razor blade and filed them sort of flat - when I re-installed the relay all was good - the wipers will shut off and park and the intermittent position works too - I don't know what caused the initial melting of the contacts and i'm going to get a new relay in any case - so if anyone out there has the no shut off problem check the relay

[Alan in AZ]

Don't get a Porsche replacement relay - they are expensive and don't operate very well functionally (silly wheel to set delay - what a stupid idea - which way make it longer vs shorter? - who knows, have to try it to find out, and then forget again...)

Get the VW programmable delay relay - direct replacement all years - set the delay by pulling the stalk instead digitally - pull the stalk when you need the wipe - no futzing around with the silly wheel.

Feeling lazy - you get an ~6 second delay by default.

Intermittent Wipers - couldn't they be better? - Rennlist Discussion Forums

Alan

[honerboys]

alan i was hoping you'd chime in on this - thanks - I read the rennlist link - this sounds like the way i'll go - I see the 3B0-955-531 is available for around $40 - another problem solved - car is getting close

[Danglerb]

I found a cross reference, which I think is the correct relay, but wise people would wait on verification.

Relay, Wipe-/Wash Interval 0986335058 Bosch

AUDI 431 455 531
CITROËN 6555 11
CITROËN 6555 34
CITROËN 95 495 006
OPEL 1238550
PORSCHE 928 615 101 01
SAAB 85 83 627
VOLVO 32017246
VW 191 955 531
VW 321 955 531 A
VW 357 955 531
VW 3B0 955 531

[honerboys]

strange that when I put this (0986335058 Bosch) in an ebay search all the results are in Europe - and it does have a 928 part number (928 615 101 01) - so was this relay only offered in ROW cars while America got the little wheel under the dash - the relay I now have is 928 615 101 00...hmmm

[SwedeInSiam]

RoW cars also have the wheel under dash.

[honerboys]

well at least I know we weren't ripped off

[Danglerb]

Current Porsche part number I see is 993 or something like that instead of 928, and indeed it makes no sense to me unless people are claiming these are compatible or just confused.

All the cars listed or almost have some forum thread where people look for the replacement where the delay is set by time between manually switching to interval wipe. I decided it will stop raining in Calif for the year by the time I might figure it out and order one.

Those less cheap than me, call a knowledgeable 928 vendor who should know the part we need.