Headlight Washer & Heated Mirror Questions

[Huw Powell]

> ** Headlight washers: truly broken, and the mystery deepens.
>
> Truly broken I'm afraid. I only just ordered the factory manual (on CD-ugh,
> paper is no longer available-ugh!) and wiring schematics today, so any help
> would truly be appreciated. Here are the symptoms and diagnostics so far:

I love it.  You have the manual and have done some thorough diagnostics
before pursuing the question!  cool...

>
>         All fuses (#3 and #24 if memory serves) are good. With plenty of
> fluid and the lights on, of course :-), when I pull the wiper stalk switch
>
> 1.      The windshield sprayers spray and wipers wipe
> 2.      One second after that a relay clicks on and voltage appears at the
> terminals of the headlight washer motor.
> 3.      One second after that the relay clicks off and there is no voltage
> at the terminals of the headlight washer motor. 2 & 3 happen whether or not
> the headlight washer motor is hooked up.
> 4.      Attaching the headlight washer motor directly to the battery nothing
> happens. The motor coil measures 1.8 ohms.
>
> If the motor is bad, would that kill the relay? I wouldn't think so. I
> assume the headlight washer relay should stay energized from 1 second after
> the windshield sprayers start until the stalk switch is released. Why is it
> going off after 1 second? Perhaps I have two separate problems, the motor
> and the relay? Maybe a good starting place is the relay. Which relay is it,
> and how does the manual say to test it?

Admittedly my experience is with systems of a decade prior to your car,
but often there is a lot of continuity to how Audi does things.

pump motor resistance sounds right.  did you try hooking it up the other
way (12/gnd switch?)  Anyway, assuming for the moment that it is dead
since it sounds like it (and why??)... check inside it for obstructions
maybe?

on my 90Q, the headlight washers *do not* appear to stay on as long as I
hold the stalk.  They turn off pretty quickly - I think - and one second
might be about right.

if you had access to a known working pump it would be interesting to see
what happened.

I *think* the pop up sprayers are pressure driven, maybe someone who
*knows* can verify?

--
Huw Powell

http://www.humanspeakers.com/audi/

http://www.humanthoughts.org/