[AT] tractor hauler a pain to install headlights.

[Steve W.]

Brian VanDragt wrote:
> Yes it is 80%.  There is very little increase in brightness when I turn 
> the light switch on.  Maybe its different on today’s cars, mine is 21 
> years old.  My DRL’s are not separate light bulbs, they are the actual 
> headlights.
> 
> Brian
> 

Not saying you're perception is wrong but pretty much all of the 
headlamp DRLs out there work the same way. They run battery voltage 
through the high beam lights in series so you get about 6 volts through 
each lamp. Most do it simply be switching one lamp in and out of the 
ground circuit using a couple of relays. On some of the "fancier" cars 
they do it by using PWM switching to lower the light output.


-- 
Steve W.