Hello,
I'm currently working on a project where I'm re-running all of the power wires to my headlights and using relays in order to make the headlights brighter, and I got to thinking that it'd be really cool to have my high beams light up partially when just my low beams are on, and fully light up when the high beam switch is engaged. In order to do this, I'd need to supply less than twelve volts to the high beam bulbs when just my low beams are on, which I could easily do through the use of relays and some tricks to reduce voltage to a suitable level.

I'm just curious as to whether or not it's bad for headlight bulbs to run at less than twelve volts. I know that up in Canada the high beam bulbs are on, but not at full power when the DRLs are on, so this leads me to think that it wouldn't be bad for the bulbs. Also, in my friend's SPW catalog, they had a device to reduce headlight brightness with a knob, and I'm guessing that it just reduces voltage to the light bulbs. I just want to be sure, so does anyone know if it's bad for 9005 headlight bulbs to run at a level that's less than twelve volts. I'm just randomly guessing that I'll want them to run at around eight volts. >> Thanks in advance for any help you guys can give me.

By the way, if this all works out well, I'm going to write up a nice how-to to do this. >>

No it wouldny hurt anything. The only down side would be that the bulbs might go out faster but it would look cool and very different so who cares if you have to replace them sooner. Good luck and let me know if you run into any wiring problems and ill try to help.

Thanks for the reply. Do you think it'd significantly reduce the bulb life? I have bulbs that are discontinued, and I really like them and don't want them to blow anytime soon.

It wont be that bad. they should last as long as your low beams do now. My last car had day time running lights and i had to get bulbs every 10 months or so.

seeing how heat is what kills a light bulb... running less volts to them should make them last longer... but anyway if you do. do this please do a how-to on it i would love to see how you do it'.. i have an idea but i never think like other poeple

-macavely+Sep 3, 2003 - 8:17 PM

if u just want all four of ur lights on when driving. i put sum leds inside the high beam. just drilled a hole and placed a 12v led then silicones it all nice. then i wired them into the running lights. its cool looking ill take a pic soon.

-x_itchy_b_x+Sep 4, 2003 - 3:23 PM

oh, good call i wish mine were a tid brighter.

Follow ups?

i was thinking along the lines of putting side marker lights in the high beams? (not actually doing that)