Does anyone know where the intermittent wiper relay is located? My wipers still work but the intermittent wipers only come on once when they are turned on. I suspect the relay took a **** but can’t find its location. Any help would be greatly appreciated.
Chris
Chris - sorry. After about 20 minutes of searching AllDataDIY I failed to come up with a component locator diagram. That's a rather serious missing tool for a DIY or a pro mechanic. I'll poke around the web a bit and see if anything pops up - often parts diagrams can give a clue where the relay is.
BTW - I deleted the 2 duplicate posts you'd made earlier.
Thank you for taking time to look. I have looked all over the place myself and can’t come up with anything.
Sorry about the multiple posts. I kept getting an error when I posted it and didn’t realize it was actually working.
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Are you sure there is one? I think the wiper system is controlled by the Vehicle Electrical Systems Control Unit. If you have rain sensing wipers, then you also have that circuit by the rear view mirror.
Thanks Zach. I am not sure if I have a relay or not. I do have rain sensing wipers. I do have a sensor up by the mirror. I wonder if that sensor might be bad. Do you know how that sensor works? Are the sensors reading sound or moisture?
Chris
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The rain sensor is actually optical and is mounted up by the rear view mirror. I guess if that optical path is blocked, that could be your problem. Any chance you got a new inspection sticker? The sensitivity on the sensor is controlled by a little slide on the right stalk on the steering wheel. You should play around with that also. If you want to try to debug further, there are 4 wires that come out of the rain sensor. Colors are at the rain sensor, some of them change colors at a connector before they get to the VESCU(Vehicle Electrical System Control Unit). There are two brown wires. One is a local ground. The second is called "rain sensor -". I assume that is ground also but not sure. That feeds back to the VESCU. There is a green wire. That is "rain sensor +". That also goes to the VESCU. Lastly, there is a brown wire with a green stripe. That is your rain sensor "signal" wire. I'm assuming that gets pulled high (or low) to make the windshield wiper do a single swipe. I little poking with a volt meter and maybe a voltage/ground probe should let you figure out if that is working or not. I haven't tried it myself though.
Chris - after about an hour of web browsing and coming up with nothing, I went to the factory service manual. There is no wiper relay. The car uses a computer module to control the wipers. I believe this started with the option of a rain-sensor. If your car has a rain sensor, chances are it's kaput or out of calibration. If your car doesn't have one - then the control module perhaps thinks it does (programmed incorrectly) and is looking for the signal from the sensor to trigger the wiper. The initial wipe would be a wakeup wipe, something done with rain-sensor systems in immediate response to the user input.
Here is a diagram for the system. Arrows point to the control unit, and to the wiper wiring. Note that there is no relay between the two. The control module undoubtedly uses an electronic switch to trigger the wiper, no moving parts, no contacts, all done with solid-state components.
HTH:
Thanks to all that have commented on this post. I am a dumb ***. The car hasn’t been out in the rain for about 3 months or more. I just realized that the windshield sun strip that I put on it back in the winter covers the rain sensor. I should have realized it sooner because my Cayenne has rain sensing also but when the tinted windshield strip was installed by the tint shop they trimmed around it. I’m sorry I wasted your time.
Chris
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- Really. Thanks for letting us close out this diagnostics session...
Nothing wrong with making a mistake - that's how we all learn. Thanks for admitting it and letting people know what happened, that's what's the MOST valuable thing! Kudos!
