# Headlight Windshield Wipers...Pretense Or Function? **URL:** \ **Category:** Factual Questions\ **Created:** [August 16, 2008, 1:02pm UTC](https://boards.straightdope.com/t/headlight-windshield-wipers-pretense-or-function/460214 "2008-08-16T13:02:38Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![FoieGrasIsEvil](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/foiegrasisevil/32/16638_2.png) [@FoieGrasIsEvil](https://boards.straightdope.com/u/FoieGrasIsEvil)\ **Post date:** [August 16, 2008, 1:02pm UTC](https://boards.straightdope.com/t/headlight-windshield-wipers-pretense-or-function/460214/1 "2008-08-16T13:02:38Z")
What can these things do, really? So, In a heavy rainfall at night, do the wipers reduce diffraction or diffusion of your headlight’s beam, giving you more visibility? I can’t help but wonder if they do anything meaningful other than provide the dealer with yet another moving part to fix later. ---
**Author:** ![enipla](https://avatars.discourse-cdn.com/v4/letter/e/54ee81/32.png) [@enipla](https://boards.straightdope.com/u/enipla)\ **Post date:** [August 16, 2008, 1:56pm UTC](https://boards.straightdope.com/t/headlight-windshield-wipers-pretense-or-function/460214/2 "2008-08-16T13:56:40Z")
[QUOTE=FoieGrasIsEvil] What can these things do, really? So, In a heavy rainfall at night, do the wipers reduce diffraction or diffusion of your headlight’s beam, giving you more visibility? I can’t help but wonder if they do anything meaningful other than provide the dealer with yet another moving part to fix later. [/QUOTE] They are to clean road grit and grim off your headlights. This does help if you are in a place that gets a lot of snow and they use Mag Chloride (a de-icer) on the roads. I don’t have them, but I do grab a handful of snow and scrub mine off during the winter. And it makes a pretty big difference. ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [August 16, 2008, 2:07pm UTC](https://boards.straightdope.com/t/headlight-windshield-wipers-pretense-or-function/460214/3 "2008-08-16T14:07:29Z")
[QUOTE=enipla] I don’t have them, but I do grab a handful of snow and scrub mine off during the winter. And it makes a pretty big difference. [/QUOTE] Exactly. I don’t know if the wiper implementation works but the problem is definitely real. ---
**Author:** ![Throatwarbler\_Mangrove](https://avatars.discourse-cdn.com/v4/letter/t/8c91f0/32.png) [@Throatwarbler\_Mangrove](https://boards.straightdope.com/u/Throatwarbler_Mangrove)\ **Post date:** [August 16, 2008, 2:24pm UTC](https://boards.straightdope.com/t/headlight-windshield-wipers-pretense-or-function/460214/4 "2008-08-16T14:24:08Z")
There was a thread on this already a few months ago. I don’t think there are any modern cars that use wipers, it was an early 90s thing. The old Mercedes I use to have had a common problem in that the headlight wiper motor would short out and cause an engine fire, and many people simply removed them as a preventative measure. Most modern cars use a spray only. European regulations require them for HID (High Intensity Discharge) headlights, because the increase light output of those lights can result in glare to oncoming drivers if they are dirty. The wipers seem to have been a European thing, I have never seen American or Japanese cars with them. ---
**Author:** ![jasonh300](https://avatars.discourse-cdn.com/v4/letter/j/46a35a/32.png) [@jasonh300](https://boards.straightdope.com/u/jasonh300)\ **Post date:** [August 16, 2008, 4:19pm UTC](https://boards.straightdope.com/t/headlight-windshield-wipers-pretense-or-function/460214/5 "2008-08-16T16:19:28Z")
I saw a GMC (Tahoe maybe? Boxy SUV) yesterday that had washers on the headlights. That’s the first American car I’ve ever seen with them. ---
**Author:** ![GaryM](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garym/32/241_2.png) [@GaryM](https://boards.straightdope.com/u/GaryM)\ **Post date:** [August 16, 2008, 9:00pm UTC](https://boards.straightdope.com/t/headlight-windshield-wipers-pretense-or-function/460214/6 "2008-08-16T21:00:48Z")
The Chevy Caprice my wife bought before we met had sprayers for the headlamps, and that was a 1969 model. ---
**Author:** ![Tamex](https://avatars.discourse-cdn.com/v4/letter/t/ccd318/32.png) [@Tamex](https://boards.straightdope.com/u/Tamex)\ **Post date:** [August 17, 2008, 5:50pm UTC](https://boards.straightdope.com/t/headlight-windshield-wipers-pretense-or-function/460214/7 "2008-08-17T17:50:46Z")
I’ve never seen headlight wipers, but I agree with **enipla** that if they worked, they would solve a real problem in the winter. I usually wipe the headlights off with the window washer at the gas station. It would be nice to be able to wash them off as you go like you can the windshield. ---
**Author:** ![jasonh300](https://avatars.discourse-cdn.com/v4/letter/j/46a35a/32.png) [@jasonh300](https://boards.straightdope.com/u/jasonh300)\ **Post date:** [August 19, 2008, 12:38am UTC](https://boards.straightdope.com/t/headlight-windshield-wipers-pretense-or-function/460214/8 "2008-08-19T00:38:01Z")
[QUOTE=GaryM] The Chevy Caprice my wife bought before we met had sprayers for the headlamps, and that was a 1969 model. [/QUOTE] I had some experience with a '69 Caprice in my early teens…my aunt wasn’t driving it anymore and parked it by my house for a while. I got ahold of the key and proceeded to modify parts of the engine. That particular car didn’t have sprayers on the headlights, but there were a lot of weird options for the Caprice including covered headlights, electric windshield de-icer, etc. (covered headlights weren’t really weird, but they were pretty rare on the '69 Caprices). Was your wife’s Caprice a two-door? (I’d love to get my hands on one of those)