CaptPegLeg

Anyone have problems with the rain sensor function of the wipers? What kind of solution?
During my first trip back to the dealer, the service dept. assured me they were working properly and offered to demonstrate using a spray bottle. This was of course after detailing the car. I passed on the demo and waited for a real world situation with rain. This is only the second time it's rained since purchase but we finally have some rain. I took a series of photos during a 40 second period showing the rain on the windshield (I attached the first and last in the series). Once during the hour or so of driving in the rain the wipers seemed to work properly for 6 or 8 cycles during a 30 second period.
Unless I take it to the dealer while it's raining, (3 1/2 hours away) I am sure they will find it works fine for them using their spray bottle demo. Maybe I am just expecting to much from the system but I don't think so.
I appreciate any suggestions.

Sloth

What kind of problem are you asking about? From my own experience, it never seems to run fast enough to keep the windshield clear in heavy rain. Playing with the switch on the end of the lever doesn't seem to help any. In that situation I manualy put the wipers to the full speed position.

Shamus

When it is raining I leave my wipers on the autosense position and they work perfectly.

dlipetz

I've found that the switch at the end of the lever seems to increase sensitivity, but may just be my imagination.

eugkim

I haven't had a problem with them - I leave them in that position when it's raining. The only thing I found is that it won't continue to work if you turn off the ignition. I have to bring the stalk back to the neutral position, then back to the automatic one to work.

alex911s

I agree, I think you have to put wiper lever in zero postion then back on to position 1 to turn them on. It doesnt go on auto if you leave it in position 1, unless there's something worng with mine, but this is my 3rd cayenne they all work the same.

dlipetz

This is by design, same on my X5. If it didn't work that way you'd wish it did when you went through a car wash and forgot to turn them off!

CaptPegLeg

I realize that you have to restart the system each time you turn on the ignition. The sensitivity switch at it's highest setting is what I've been using. I don't know if it would ever wipe at the lowest setting. As you can see from the photos above, the sensor is just not sensitive enough. It was a light but steady rain and it was 40 seconds between the two photos with no wiper action at all. From the comments, it seems like my problem may be unique.
I guess short of having the car at the dealer on a rainy day, I just need to stomp and have them replace the sensor and see if that helps.
There is a dealer within 2 hours but the one 3 1/2 hours away is where I purchased and where they have already assured me the wipers work properly. I guess I also want them to admit there really is a problem and apologize for jerking me around on what should be a simple fix.

ltc

Class...pay attention....


Rain Sensor and Intermittent Settings
The rain sensor on vehicles so equipped measures the precipitation on the windshield, including snow. Correspondingly, the wiper speed/frequency is automatically set between intermittent to continuous (Stage 1 and Stage 2). The rain sensor function supercedes thet interval function.

The following will activate the rain sensor:
Setting the wiper lever from Neutral to Stage 1
Operating the windshield washer system
Changing the rain sensor sensitivity with the thumb wheel.
Activation of the rain sensor is confirmed by a single wipe of the blade.

Function
Increasing the sensitivity by the potentiometer on the wiper switch triggers a single wipe cycle, thus transmitting information to the rain sensor via the serial interface. During the pauses in wiping, the wiper is placed into a raised "Interval Parking" position and is protected against backlash by the motor.
Activation of the intermittent operation immediately results in a full wipe cycle. Thsi does not occur, however, if the intermittent function was active before the ignition was switched on. If the rain sensor does not receive a signal after a specified period, the intermittent operation stars with one wiping cycle. The interval pause is determined by the wiper set point, vehicle speed and potentiometer value.
The wiping speed during intermittent operation corresponds roughly to Stage 1. Shortening the interval pause on the potentiometer triggers a single wiping cycle.

Automatic Reduction of the Wiping Frequency
This function is activated after the ignition is switched on (terminal 15) and the vehicle achieves a speed of > 5mph. If Stage 2 has been selected and the vehicle speed is greater than 5mph, the wiper operates at Stage 2. If the speed goes below 2.5mph the wiper speed switches from Stage 2 to Stage 1. If the vehicle speed increases again to > 5 mph, the wiper, depending upon the lever setting, will run at Stage 2.

If Stage 1 has been selected, the wiper speed is set to Intermittent if the vehicle speed is < 2.5mph. The interval pause period is 4 seconds. If the vehicle speed returns to above 5mph the wiper again operates at Stage 1.

Automatic decrease of wiper speed is interuupted by a function modification on the circuit. The automatic decrease in wiper frequency resumes after the vehicle speed reduces from > 5mph to below 2.5mph.

...Class Dismissed ...

CaptPegLeg

Lewis, just curious, ever write any software user manuals?

ltc

The above excerpt is from the Porsche factory documentation provided to their technicians.
(BTW, no, I only do H/W.)

The wiper system is a bit of an enigma. I've never really been happy with its operation vs design intent, so I normally just end up using the wipers manually....except of course in the 'early' days, when before the 2 wiper replacement TSB's, you had to shut the wipers off because you couldn't stand the sound of 2 angry elephants being dragged across the windshield.....OK, so Valeo had a few QC problems with early wipers.

Hope the info made some sort of sense.......besides, I always wanted to use in a post, so the timing seemed right

PTEC

Or in the case if you left them on and came back to a car that was buried in snow, the motors wouldnt burn themselves out trying to move against the weight of the snow.

CaptPegLeg

Just an update, if you have the windshield replaced, you must also replace the rain sensor. That is what the glass guy said after doing his research. I got a rock chip on the way home from purchase and had to replace the glass but he didn't know the sensor had to be replaced as well,

JFScheck

Yea, had a rock chip patched and my windshield guy told me it's almost impossible to remove that rain sensor on the glass without breaking it.

skl

I'd like to deactivate the rain sensing function if I could and just be able to have intermittent wipers I can set the frequency on. I have a good layer of RainX on the windshield and don't need them going all the time. In fact, if it's not raining real hard you don't need them on at all except when passing or following a big semi. Any way to just turn that function off ? ( a fuse to remove somewhere perhaps?)