[928uk] Wiper stalk

[Paul R Smith]

First, something you need to be aware off before any trial and error 
diagnosing, When we want the wipers to stop (park) the motor is short 
circuited. This is a trick that works with this type of motor, short 
circuit it and it stops much more promptly than if the power is just 
disconnected. What this means is that the high speed input to the motor 
is grounded when the motor is in the park position and the switch is in 
the off position and the intermittent wipe relay is in the rest 
position. So if you applied 12v to the high speed input to the motor at 
that time, you would melt your test wire and the other wires involved.

This also means that it is important that the "0" position contact in 
the switch must open correctly when the switch is moved.

Now, each of your problems could be caused by other things (e.g. motor 
or relay) but three together does make the switch the most likely 
culprit. You could try spraying in some contact cleaner and working the 
switch, but if that doesn't work, you are either looking at drilling out 
the rivets (or finding someone who will) or replacing it.

Smiffy

On 06/01/2025 15:51, 21Gmail via 928uk wrote:

Dear 928ers,

It’s been quite some time since my last question…

I’m finally getting round to putting the interior back into my MY84 928 and trying to deal with some electrical issues (for which I’m really not qualified).

The wiper stalk seems to:
- only work on 1 (slow) & 3 (v fast).
- position 4 (intermittent) doesn’t work.
- 5 & 6 (washers) seem to work ok.
- using 1 & 3 to get them working requires manual timing when switching them off to get the wipers at the bottom of the windscreen.

I’ve taken out the stalk mechanism and can see it’s sealed / not openable. I was hoping I could get to the stalk trigger and see if there are any problems with the contacts.

Is there anything else that might be causing the problems? Is there anyone who reconditions these things?

Any advice will be gratefully received.

Thanks
Mike

928 MY84 Auto

Sent from my iPhone