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A few weeks ago I was coming back from Quebec and got caught in a terrible ice rain. My entire car was covered in roughly 1cm of ice. Most of Audi s4 have headlight washers that come out on random winshield washer triggers. My concern became that while headlight washers were blocked by ice I must've kept on triggering them once in a while, while driving. Would that possibly damage the little motors driving headlight washer mechanism?

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    I'm not sure, but I thought the little things used the pressure of the fluid coming out of the nozzles to extend them. If so, there shouldn't be an issue. Either way, if they work when not frozen, I'd suggest your answer is there. I'm not completely familiar with how the Audi washer works, so leaving this as a comment. – Pᴀᴜʟsᴛᴇʀ2 Jan 15 '17 at 17:56
  • Puzzled here. Are you talking about the washers, which spray fluid on the headlights, or the wipers that move across the headlights in a manner similar to windshield wipers to clear water drops and dirt away? – dlu Jan 15 '17 at 17:57
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    Sorry about the confusion, I am referring to headlight washer that pops up from the bumper and sprays headlights. – eYe Jan 15 '17 at 18:02
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    Would guess that @Pᴀᴜʟsᴛᴇʀ2 is right, fluid pressure will be used to push out and, perhaps, open valve with return by a spring. No problem at all if it can't open for some reason. – dlu Jan 15 '17 at 18:43
  • Is the washer stuck open? Is that the real problem? Or is the picture just showing us what you were talking about? – Pᴀᴜʟsᴛᴇʀ2 Jan 15 '17 at 20:18
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I'm not sure, but I thought the little things used the pressure of the fluid coming out of the nozzles to extend them. If so, there shouldn't be an issue. Either way, if they work when not frozen, I'd suggest your answer is there.

  • On my S4, the nozzle is activated by the water pressure (it says that in the manual). – Andrew Leach Jul 1 '17 at 8:55
  • @Andrewleach - Thanks for the confirmation. :o) – Pᴀᴜʟsᴛᴇʀ2 Jul 1 '17 at 11:59
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If the headlight wiper blades were blocked from movement and they have a positive drive (where the blades must, try to, move when the system runs) then it is possible that they were trying to run and stalled by the blades being trapped in ice as you are thinking. When a motor is stalled it draws a lot of current and could overheat. A well designed motor circuit will include a fuse or circuit breaker that would trip to protect the wire (and the motor) or else it will be designed to be "inherently safe" and the mechanism will allow the motor to run without overloading. For example using pressure developed by the pump to move the arms. The pump could "spin its wheels" if the nozzles were blocked preventing damage.

The scenario that you describe is common enough that I would expect the designers to have considered it. If the wipers still work, then odds are fair that no damage was done. If they don't there first thing that I would do is to check for a blown fuse.

  • I think you misunderstood the question. He is talking about the sprayer nozzle below the headlight, as shown in the photo. This car has only the sprayer for the headlight, and no wipers on the lights. – PhilippNagel Jan 20 '17 at 19:55

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