Co-incidentally, as I have been learning the ways of the wiper-motor, my local friend; yes I do have the one, (let's call him "Mike", because that's his name) mentioned that his wipers didn't park at all.
Of course, I now have the answer to what is most likely to be the cause of this problem, so I thought you might all get the "benefit" of my wisdom.
Before getting too technical about this it's obviously worth first checking for basic wiring problems. There should be four wires with spade-connections to the wiper switch and it's worth removing these one by one and cleaning and lubricating the terminals. Likewise at the plastic plug and socket joint close to the motor it's possible that the terminals are corroded or not fully engaged. But in my experience these are unlikely to be the cause of the problem and it's more likely to be the parking switch inside the motor.
Removing the motor to examine this is a PITA and I'm not going to depress myself by describing it here. But once you have it on the bench it should become very easy.
You need a small screwdriver to remove the four small setscrews which secure the square, plastic gear-cover. This will not come off completely because of the soldered wires, but it easily allows access to see the white plunger of the switch. This plunger is depressed once on each revolution of the motor when it reaches the raised cam. So at all other points there should be continuity between the connections on the back of the plate. If you find it is open-circuit this means either the plunger is stuck or the switch contacts are dirty. Getting at the contacts would be a bit involved and need the little rivets to be removed. I suggest that you avoid that and just spray in a drop of WD40, penetrating-oil or contact-spray and manipulate your plunger a little.
Whilst you're there it makes sense to slop in a blob of grease to bolster the 50 year-old gunge that remains.
This should sort things out and when re-assembled, the regular use you will now put your car to in the rain should keep it well exercised.
Of course, I now have the answer to what is most likely to be the cause of this problem, so I thought you might all get the "benefit" of my wisdom.
Before getting too technical about this it's obviously worth first checking for basic wiring problems. There should be four wires with spade-connections to the wiper switch and it's worth removing these one by one and cleaning and lubricating the terminals. Likewise at the plastic plug and socket joint close to the motor it's possible that the terminals are corroded or not fully engaged. But in my experience these are unlikely to be the cause of the problem and it's more likely to be the parking switch inside the motor.
Removing the motor to examine this is a PITA and I'm not going to depress myself by describing it here. But once you have it on the bench it should become very easy.
You need a small screwdriver to remove the four small setscrews which secure the square, plastic gear-cover. This will not come off completely because of the soldered wires, but it easily allows access to see the white plunger of the switch. This plunger is depressed once on each revolution of the motor when it reaches the raised cam. So at all other points there should be continuity between the connections on the back of the plate. If you find it is open-circuit this means either the plunger is stuck or the switch contacts are dirty. Getting at the contacts would be a bit involved and need the little rivets to be removed. I suggest that you avoid that and just spray in a drop of WD40, penetrating-oil or contact-spray and manipulate your plunger a little.
Whilst you're there it makes sense to slop in a blob of grease to bolster the 50 year-old gunge that remains.This should sort things out and when re-assembled, the regular use you will now put your car to in the rain should keep it well exercised.
