RE: H4/H1 light strangeness

[lee@wheelman.com (Lee M. Levitt)]

ti@amb.org (Ti Kan)

> Michael Williams writes:
> > [ H4/H1 light strangeness ]
>
> You do realize that the H4 bulb's pinout is different than the stock
> seal-beam DOT lights right?  Looking from the back of the bulb:
>
>     B
>    --
> A |  | C
>
> DOT: A=low beam (yel), B=high beam (wht), C=ground (brn)
> H4:  A=ground (brn), B=low beam (yel), C=high beam (wht)
>
> Just in case this difference in wiring is the cause...
> Also, maybe there is still something wrong with your headlight switch.
>


Yes, the pin difference will cause the H4 high beam to light dimly when the
switch is set to low beam. Had this very problem when I installed a set of
H4/H1 quad lamps on an old Volvo...couldn't figure out what was up until I
added in the pigtail changeover that came with the lamps. Interestingly,
when I upgraded my Range Rover with round 7" H4s this wasn't a problem.
Wonder if its only on multi bulb setups...

Lee