Mine is in a zipped cover on the inside, but in 9 1/2 years it has never given me any issues at all so have never even looked inside the cover. How old is your 640?

 

Mine is in a zipped cover, accessed from the berth,behind the steering wheel . Its a simple wiper motor which directly drives the wiper through the windshield by way of spline shaft protruding from the motor. Mine stopped working and a replacement motor was easily fitted. No need to remove any parts of the vinyl screen. Just unzip the cover and remove the motor.

 

mine the same

 

I think he's got a weekender, not a pilot house?

 

Hi
Thank you yes it a a weekender, motor cleverly built in above screen behind stuck on vinyl panel and an overhang at front over the screen and wiper blade connection, the motor goes slowly then blows fuse do you think its the motor could it need a wd 40 squirt if I can remove it.
BarryG

 

It cannot hurt to try WD 40 first if you can get to it