Do You Have To Refresh You Wipers?

[CPAudi8]

I have a 2011 A8, I have an issue with my wipers when I leave them on auto, that if sometime when it is raining when I start the car the wipers will never start unless I set the wiper stalk to off then back to auto.

I have taken the car into the dealer a few times and have eventually been told this is normal behaviour which I do not agree with.

The problem has got worse and now some times when the stalk is set to low the wipers are not coming on when I turn the ignition on. This is very intermittent and I have not managed to demonstrate it to the dealer so they are maintaining it is normal behaviour.

I fail to see how this is not a fault, can anyone tell me either way?

Thanks
Colin

[Guest 2]

I have a 2011 A8, I have an issue with my wipers when I leave them on auto, that if sometime when it is raining when I start the car the wipers will never start unless I set the wiper stalk to off then back to auto.

I have taken the car into the dealer a few times and have eventually been told this is normal behaviour which I do not agree with.

Normal, you can also get them going by keeping them in auto and moving the sensitivity switch.


The problem has got worse and now some times when the stalk is set to low the wipers are not coming on when I turn the ignition on. This is very intermittent and I have not managed to demonstrate it to the dealer so they are maintaining it is normal behaviour.

Again, this is normal.

[CPAudi8]

Wow....

Thanks for the fast reply

The car didn't do it when I first got it only seems to have done it over the last 6 months.... neve had any other car which did this, it seems a bit of a failing on such a high end car.

[snapdragon]

My D3 and the D4 I had for a week they would start automatically in the rain, but only when moving forward >5mph.

[Micha_elD]

It worth getting to understand how the wiper sensor works, then it all makes sense.

The sensor shines a LED light at an angle to the window, and measures how the light reflects off the glass. If raindrops fall onto the part of the glass being monitored, then the light will be redirected, and the sensor will see the change, and know that a raindrop just arrived.

The sensor will be reset when you turn on the ignition, and if the amount of reflected light stays the same, then the device will think that its still dry. Only, the glass was wet when you switched on the ignition, and it stays wet, then the sensor will think its dry and stayed dry, so ... no wipers. One wipe, and it will then be able to see any drops arriving as a change, and everything works OK. That is your 'refresh' of the wipers.

If you set off with a wet screen, and the speed of the car moves the water around, then the sensor will see the change, and trigger the wipers, but only if you go fast enough to move the water.

If the car is new, screen is polished (or Rain-X'd), then the water will move off the screen sooner, so your auto wipers will work as you want. But if the screen if a bit grubby, then the water will stay on the screen for longer, so after the car gets a bit mucky, it won't work as well as it did when new with a clean screen.

Hope this helps

[snapdragon]

Superb description.

[Guest 2]

Superb description.

Ditto!