From: Wally Plumley [wplumley@bellsouth.net]
Sent: Tuesday, March 27, 2001 12:30 PM
To: 928
Subject: [928] Re: How does the rear wiper know where to park itself?

At 11:12 AM 3/27/01, David E Bruschi wrote:
>Can anyone tell me, how the rear wiper knows where to park it self?  My
>motor and switch seem to work fine, but the wiper usually goes across a
>couple times, three I think and then stops wherever it feels like it.  To
>combat this I cycle the wiper a couple times and then by pure luck it ends
>up back on the left side. A minor issue but frustrating none the less.


The rear wiper momentary switch energizes the electronic control inside the 
rear wiper relay (mounted next to the wiper motor). This energizes the 
relay contacts, which turns on the rear wiper motor. After about two or 
three seconds, the rear wiper relay turns off, removing the power that it 
furnishes to the wiper motor. There is a separate power supply directly to 
the rear wiper motor thru fuse #18. Inside the wiper motor, there is 
another set of contacts, operated by the wiper drive mechanism. These 
contacts connect the separate power supply to the wiper motor. The contacts 
are closed except when the wiper drive mechanism is in the park position, 
so if the wiper is away from the park position when the relay cuts off, the 
internal contacts furnish power to run the motor until the wiper gets to 
the park position. At that point, the internal contacts open, and the wiper 
stops.

In your case, it sounds as if fuse #18 may be bad. If not, the internal 
contacts may be bad or misadjusted.

Wally Plumley
928 Specialists