Dim Question

[nelmo]

When you switch on high beam on a standard H4 bulb, do both filaments come on or does the dipped beam filament turn off?

 

By the way, don't try answering this by staring at your headlights and flicking main beam on, unless you want to do a Ray Charles impression for the next 10 minutes

[Shaft]

Try your Ray Charles method again but this time employ the use of a welding mask.

[fry61]

Try your Ray Charles method again but this time employ the use of a welding mask.

AND VERY LONG ARMS

[Grim]

short answer is no. One or the other. Both on main will cause them to overheat and you'll have short bulb life. If both light up on dip, you may have the pins wired incorrectly

[cb750]

As above, usually one or the other filaments. However I have owned 4-headlight cars where 2 of the lights came on when on dip and main and the outer 2 only came on on main. The idea was that when you were on main you had 4 main beams plus 2 on dip filling in the road between you and the main beam pattern

[Guest 2b cruising]

Cars with 4 different lights that I have owned have as above, dip staying on with dip when main switched on.

I've never found one with two lamps where this happens.

[Guest Ian & Carole]

The only time both dip and high beam are on together is with the flash function.

Re check how you have wired up the 3 pin plug on the head light.

 

[nelmo]

Thanks all - something was coming on but I couldn't tell if it was main or dipped. However, I think my switch is the problem...