zefke

Hello Porsche Fan's

My name is Paul and I'm new here on the forum.

I recently bought a 928S from 1984 and I'm trying to fix some broken stuff and figure out how things work.

One thing that doesn't work are the windscreen washers. So I started troubleshooting and came across these heated washer jets.

In the shematic it looks like they are hooked up to the wiper motor power constantly. So are they heated permanently or is there some other mechanism that activates them?

They are currently disconnected and I don't want to connect them before I know how they work.

Can anybody shed some light on this?

Porsche greetings
Paul

ammonman

Welcome Paul and congrats on your new to you shark. This forum is a great resource as just about any 928 problem you have has been discussed here and a solution posted. Use the search function and do a search on "windshield washer". Just be sure to put your search terms in quotes as it seems to do a better job finding what you are looking for. You will get many posts about how to refurbish the entire system from cleaning the tank and pumps to replacing the check valves and nozzles.

Good luck and welcome to the addiction!

Mike

dr bob

Hi Paul--

Welcome to the group, and congrats on your purchase!

As Mike mentioned, the search tool will be your friend on lots of things like this. But I'm not sure I remember seeing much about the heaters in the nozzles. First thing to consider is that they don't affect the performance of the nozzles except in extreme weather. They do in fact connect to an auxiliary contact on the wiper motor, but the power is flowing toward the wiper motor on that connecting wire. That's the 'park' connection on the motor, BTW. The current source is from "Connection point VII" on the diagram. The wiring diagrams for the early-mid 80's cars are tedious at best. Look at the connection designator under that "connection point" and see that it comes from C1 on the central electrics panel. That happens to be shown on page 01, where the fuse connections show C1 connected to the load side of the 16A windshield wiper system fuse, in what looks like position 6 in the CE panel. That drawing also shows that power for fuse 6 is supplied from the X-bus. That connection will be hot when the key is in the "run" position only.

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The plumbing part of the washer jets is a little complicated, thanks to the need to keep the regular washer system isolated from the intensive washer fluid system, while sharing the nozzles. Two platic tubes go into the hood, where fluid flow isolation is managed by 4 spring-loaded ball-check valves. These have an annoying habit of rusting and plugging, so the first remedy is to pull the hose manifold out of the hood and rebuild it. Our regular 928 parts suppliers here can get you the hose, the check valves, new Y connections, and a replacemnt for the fitting where the hoses enter the hood, the one with the little plastic nipple broken off. None of these pieces are expensive. Before you extract the old hosem tie a string to it from the driver's side, and pull the end of the string back through as you get the hoses out. That string will let you pull the new hoses back in and save you a bunch of fishing in the hood itself. There are several good writeups on users' tips pages (links to them in te "new user" thread at the top of the first forum page...) regarding the hose routing, replacement, washer pump clean and service, etc.

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I'm not sure if the search function is available to non-members. With your new car, you'll have plenty to do bringing stuff like this current, so access to search will save you lots of time and aggravation. Membership is relatively cheap compared to the first project costs, pays back multiple times easily.

Also, take a minute to fill in some info on the 'User CP' tab, stuff like the year of the car and where you are located. There are listmembers scattered all over the place, with support groups active in many of the larger concentration areas. And before someone else pipes up, post a few pics of the car, and some background on how you acquired it, etc. There's always a good story lurking inside every car purchase.

Landseer

The fill inlet to the washer reservoir has a pair of mild steel inserts that invariably deposit large quantities of rust into the tank. Look at the link below (hopefully you can see the pictures as a user not member). Don't damage the black hose linking the filler and the tank because its expensive.

Be sure to remedy the rust before you try to squirt any juice through refreshed nozzles.

This write-up is bush-league in quality, but the pictures give a glimpse of the underlying issue.

https://rennlist.com/forums/928-foru...mp-repair.html

To make it a little more clear:
The little centrifugal pump at the base of the tank is for the headlight washers.
The little gear pump, mounted almost inaccesibly on the inside of the passenger fender, down low, is for the windshield.
Best NOT to use the torch until after removing the reservoir and fill neck sections.

jeff spahn

Perhaps my check valves are getting damaged because when i drive down the interstate the washer fluid will sometimes come out of the nozzles on its own, by vacuum I assume.

dr bob

Jeff--

Lots of cars have had the systems 'simplified' over the years, cutting the check valves to one each in the supply side, rather than one for each supply to each nozzle, check valves close to the nozzles. Yes, the simplified system still works, but it does leave a lot of fluid behind the nozzles to dribble or even boil out while driving. The ideal implementation has a short-as-possible hose between each nozzle and a Y, another short-as-possible hose between each check valve and a leg of that Y, then the supply hoses connect through a Y to the check valves.

Brett928S2

Hi

Heated washer jets ?????????

My S2 has not got them and never had them.... I have never heard of any 928 having heated ones ?? weird...

All the best Brett

dr bob

See Brett, that's what happens when all your focus is on what's under the hood, and not what's inside and on top.

Next time the hood is up, notice the little black wire bundles that go up into the hood directly under the nozzles. They carry current for the heated nozzles, plus one also supplies the current for the little courtesy lamp under the hood.

jeff spahn

Thanks Dr. Bob. I'll just keep wiping it up and not worry about it.

Brett928S2

Hi

Nope....when I was fitting my new 2000 hp Nitrous system , I had my bonnet off and while it was off I stripped out the whole washer pipes and jets and no electrics at all on mine.... just water pipes and jets, although I do have a single electrical wire to my underbonnet light...but thats it...

Going to have to search the PET 7 now to see if UK 928S2 are different....lol

Are you saying that ALL American 928s of ALL models have heated washers ?

All the best Brett

Brett928S2

Hi

Ok..checked Pet7 and we are both right....

On mine I have a "Nozzle" but on the PET there is also a "Black Heatable" which my S2 does NOT have , so I must assume its an option, or maybe all American cars got the option but not UK cars maybe ?

All the best Brett

dr bob

Jeff--

You can refit the whole correct system inside the hood for tens of dollars, not hundreds. Decide how much you like those little hard-water trails on your black hood.


Brett--

I can't say that all US cars have heated nozzles. IIRC, the car's I've looked at here, including James M's '85 Euro, have all had them.

Perhaps ice/snow are not an issue in the UK maket?

Brett928S2

Hi

Well on the South Coast where I live (think L.A with a LOT of rain lol) I have only seen snow/ice for around 5 days total in 10 years...

All the best Brett

zefke

Hello Porsche Fan's

Thank you for all the replies. I was wondering if I had the only shark with 3 washer systems and none working but it seems to be a standard problem.

1) I cleaned the tank and there was indeed lots of rust and also something that looked like disintegrated black rubber, which was blocking the Headlight Washer Pump. The pump is now running OK, I might still have some dirt in the hoses though.. (I'm also still working on the metal inserts)

2) The winscreen washer pump (under the expension tank) was stuck and burned out. I connected the intensive washer pump, but it seems to have some problems sucking the fluid from 40cm down below (I filled the tank just a little to try it). Is this a problem that you guys recognize or is it just a bad pump?

3) The intensive washer pump did not respond on pushing the small button under the dash, allthough the power was applied to pin 15 of relay XV it did not operate. When I manually connected pin 30 to pin 87 the pump did run. The problem was in the relay itself, there is a 555 timer IC installed which operates the relay (and pump) for a short time and then stops. There was a small 10uF electrolytic capacitor which looked very good from the outside but probable dried up on the inside. I replaced this capacitor and the relay works fine again.

There is not much info on the heated washer jets, I still wonder if they are powerd all the time???...

Porsche greetings
Paul

dr bob

Paul--

Good find on getting the intensive washer relay fixed. Few folks are willing (or capable) of doing component-level diagnosis on electrical bits any more. 555 Timer technology is almost ancient science these days.


The washer jets have power whenever the key in in the 'run' position. Power supply is via the X-relay and fuse 6, as described in post 3 above.