Wiper system stops working mid stroke .. then starts.. then stops
Just adding an additional data point to this thread for others to draw upon.
Was driving on the interstate, in the rain, up here in the Seattle area, and about 40 minutes into my trip the wipers just stop -mid wipe, in the middle of the windscreen as if I'd turned them off. I carefully work my way to the right most lane where I can slow down a bit, as visibility is getting poor now with a sheet of water on the windscreen, and the wipers do a few more strokes and stop again.
I check the stalk position, thinking I've bumped it or something.. nope, its fine. So I move the stalk to off and then up to low wiper speed again, and I get a few more wipes, and it stops in the middle of the window (the position the wipers were stopping in on the glass varied each time they stopped.. not consistent).
As I'm puttering along at 50mph on I-5 hoping not to be run over or plow into a vehicle not using lights in the dawn grey morning, I test the wipers .. and the work for a second. I realize at this point that if I just manually (down on stroke, short burst) activate them every 10 seconds or so, they will give me the normal 2 or 3 stroke sequence and park again.
I call the dealer, go get all the spare parts it could be and have a service appointment set up for a following day in case its needed, and head home with the parts while the rain had stopped ( my window of opportunity). My plan, pull out the motor and linkages and see if I can tell whats broken and replace the bad parts. I figured at minimum, I need to clean off the moving joints and relube, worst case replace the motor.
Given the symptoms of it cutting out, and then operating 20-30 seconds later again, I thought maybe the motor was overheating. There is a temperature sensor on that motor I believe.
When I got the cowling off at home I found, the area under the cowling was full of half a tree's droppings.. I not leaves but a tree seed type droppings similar to these
Basically, tree debris. A good shop vac once over to remove all the debris and I was able to then unnmount, clean and relube with lithium grease, the two arm joints at both ends.
None of the bushings appeared to be dammaged, and the wipers worked fine in the garage.
Summary
What I think my problem was, was the motor was overheating because the motor area was full of tree debris that had worked its way in. This reduced airflow and thus cooling of the motor.. and when it got too hot the protection system shut it off. This keeps the motor from burning out or worse setting that tree debris on fire along the way.
So after a cleaning of the space under the cowling and relubing the joints (may have been unnecessary) Its all together again.
I'll drive it for the next week or two in the rainy Puget Sound weather and that will tell if thats it or the motor is bad.
----
Update (Nov 19 2013) - OK its not the overheating motor.
Yesterday, as I was driving from work in a light rain, within about 2 miles of leaving the office parking lot the wipers again stopped mid wipe. Then did the usual mix of not responding to the stalk position, or wiping more than requested, or not at all, etc. GRrrr.
This morning, after having managed to make it home, I tried to recreate the failure conditions, running the wipers in the driveway with the hose providing rainwater.... 5 minutes and no failure. Hmmm.
So my current guess is it could be the relay for the wiper system, and that it is affected by vibration, or its the plug to the motor affected by vibrations. Pulling the panel off from the roof of the driver footwell (3 torx screws) I tested the big wiper relay. It
seemed seated. Pulled it out to look it over, no obvious signs of an issue, plugged it back in. As the turn signal / emergency flasher relay had failed years earlier with such unpredictable component failure, it seems like this type of failure could be another relay. Ok, off to the dealer.
But they dealer doesn't stock the relay, and its a spendy part at nearly $180 for a damn relay.. Grr.. and a week to get it in from Canada. So never mind for now... I'll see if the system works (which means more chancing it and having to drive in the rain with busted wipers). With the very bad interstate surfaces here in the Puget Sound (I-90, I-5, and Seattle/Tukwila streets) I'm thinking the vibrations did it in somehow. If it fails again (thankfully we have lots of rain now )... I'll pull it, pop the relay apart and look for a cold solder joint failure and redo the solder spots.
so at this point
*) its not an overheating motor (as far as I can tell)
*) it might be the relay failing intermittently (will see what happens)
*) could still be the motor failed (dealer service says could be a 50/50 as to which failed)
*) could be another connector failure such as the plug into the motor
If anyone has insight into their repair of a similar issue, I'd appreciate some feedback as I'd like to replace the broken part sooner than later, as each time it fails in the rain (and in the dark like yesterday) it is a really risk.
---------
Update (Nov 26, 2013)
Ok, so the dealer parts system , at least from Chaplins VW in Bellevue, WA is crap. Gotta be imported form Canada for $180+ my a$$.
The relay can be had for around $80 ($100 delivered to my door by UPS) form inside the US, and in fact, from a dealer within my state of WA.
So new and updated wiper relay now in hand (the original 4B0-955-531-A went to rev E and now is on the newest rev, rev C, so the current part is 4B0-955-531-C )... I'm just waiting for it to rain again to test things out. That would be the least expensive part to need to swap.
If that doesn't fix it then the motor swap is called for. I should know within the next 30 days as its the Puget Sound in Nov/Dec.
----------
Update: Dec 20 2013
Its been a few weeks of no rain and we finally got some rainfall and so far, the wipers are working as expected.
So short of some malfunction later in the winter, I'm thinking the problem was the WIPER RELAY, a $80-90 part online.
-----------
Update: Jan 6, 2014
Well, that wasn't it. After thinking the problem was licked, and unfortunately not having a lot of November/December rain during the commute times, in December the problem, once the rains came back, did return. Poop. Ok, so its the motor.
Motor replaced (~$230 with taxes from dealer) and a relatively straight forward and simple process to swap out. Keeping fingers crossed.
So now I'm hopefully calling it solved (lest things go south again in Jan/Feb).
1) Replace the motor first - its the most likely problem
2) Replace the relay after the motor, if the problem persists, or spring for the extra $30 for a relay and replace both motor and relay