Wiper Diagnostics

[Phil@isham-research.demon.co.uk (Phil Payne)]

In message <c=US%a=_%p=U.S._House_of_Re%l=MSG04-980311151044Z-1260@msg04.house.gov> "Forhan, Thomas" writes:

> Thanks. No, it was not me.
>
> Before I posted, I did an archive search
> to no avail. Could you point me to
> about the right date and I'll take another look.

Well, I don't think it's a major thing.

If you take the motor apart, you'll find a large copper track covering
around 150 degrees.  The way the motor works is that volts from the
switch (interval or normal) start the motor running and the arm starts
to move.  After a few degrees of movement, an internal wiper contacts
the copper track.  Even if power is now removed from the switch, the
motor will continue to move (powered via the copper track) until the
internal wiper falls back off the end of the track - in the 'park'
position.

Two things can happen:

a) The internal wiper becomes misregistered with respect to the
   output spindle, locating the 'park' position 90 degrees out.

b) The copper track can wear through, especially in vehicles in
   which the wipers have been used a _lot_ in interval mode on a
   relatively dry windshield.

--
 Phil Payne
 phil@isham-research.demon.co.uk
 Phone: +44 385302803  Fax: +44 1536723021
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