On the stalk that controls the rear windshield wiper on my 2012 Prius 4, I notice that there are two washer settings, one at either end of the spectrum. Both of them dispense washer fluid, but I'm curious as to why there would be two identical settings. Thanks.
I haven't checked mine, but maybe so that you can wash while it's off and wash while it's on? If it's on, then you would have to turn it off, then wash, then back on? ;D
Does the rear washer use fluid from the same tank under the hood? If so that's a long line to freeze, break, and leak if you aint careful.
Good question. I don't know the answer. But in any case, both washer settings on the rear wiper control produce fluid on the back window.
That's why there's "winter formulation" for windshield washer fluid. Though, you're usually screwed if it goes under -30 F. Even summer formulation is -15F. But yeah, if you're ignorant enough to use water, that could end poorly. As far as I read, they do use the same tank. There's 2 separate motors, one for the front, one for the back.
In your neck of woods maybe. Here 0F rated fluid is only for sale for a few months, dealers usually use +32F all year long, due to the VOC content law. It only freezes a dozen times each winter (down to 20 -25F overnight), but when you are caught with the wrong stuff outside, you are screwed.
Should be able to make your own mixture. Usually Isopropyl Alcohol is all the magic ingredient you need to "boost" the anti-freezing properties yourself. Just read the windshield washer fluid bottle. It should say what it contains for safety (poison) reasons. Keep in mind these are the freezing points after an "extended time". The line isn't going to magically freeze as soon as -25 is hit. It's going to take 8 hours for the crystals to form. Also, factor out wind chill. That doesn't count.
I don't think any washer fluid uses EG, it is toxic and damages paint. The Prius manual cautions one against doing that. Most fluid I have seen the label of uses methanol as antifreeze. I think IPA will do too.
Yeah, I edited after remembering that. Isopropyl/ethanol or methanol will do. I suppose my original comment was somewhat rude. Apparently California doesn't make winter mix at all due to their laws. No matter what, pure water should never be used. Good recipe for getting Legionarre's Disease.
Any additional thoughts about the original question, which is why are there two washer settings for the rear wiper?
The other two cars I've had with read wipers worked the same way. I think it's just so that you can easily run the washer whether the wipers or on or not.
