"Do not dry the headlights" - why not?

[Dappernut]

It's just come to my attention that the owners manual states in relation to washing the vehicle that the headlights shouldn't be dried.  Any ideas why not?  Seems a bit random, but pressumably there's a specific reason.

[xman]

Presumably there's the danger of scratching/scuffing/abrading the plastic covers. Same instruction applies to all models.

Edited 13 February, 2022 by xman

[Dappernut]

I'm sure you're right, however it seems strange to me that I could drive down a motorway in Germany at 120 mph with the headlights being hit by all sorts of insects and stuff, but can't dry them with a soft cloth.  Similar there doesn't seem to be any mention of not washing then.  Odd.

[BoxerBoy]

I guess I missed that page in the handbook so haven’t had any sleepless nights.

[SC03OTT]

Does it say don’t dry them? Or don’t “dry wipe” them.  They’re both different statements. I thought it was the latter. 

[xman]

Yes. You thought wrong 😉

[wokwon]

The polycarbonate is covered with a thin film to slow the clouding/yellowing that raw polycarbonate gets.  You have to be gentle when wiping them, especially if dust is on the cloth or polycarb.  Presumably this is something to do with blocking UV but I'm not sure and haven't looked into it.

 

Basically treat them the same as plastic eyeglass lenses that also usually have films (e.g. anti reflection films).

 

If you damage the film, you'll just have more scratches, unevenness and potential for clouding or yellowing all of which are treatable; just that if you're careful then you won't have to treat it.

 

As a poster above said, you can't avoid rocks, bug guts, birbs, birb poo etc but you can avoid damaging it yourself.

[silver1011]

Wiping a dry cloth over a dry plastic lens results in one thing, lots of small scratches...

 

 

As LED headlights get brighter, then the chances of dazzling other roads users with poor condition lenses is also likely to increase.