fog light wiring

Jim Wright wrightj@apple.com
Wed, 24 Apr 2002 21:41:04 -0500


On 4/24/02 6:30 PM, "EEYORE5182@aol.com" <EEYORE5182@aol.com> wrote:

> ok, i just got a set of piaa 1100x driving lights.  ideally, what i want to
> do is to now use the included wiring, but actually wire them with the stock
> foglight wires.  i plan on removing my stock fogs and place the new lights in
> their place.  i want to be able to use the stock wires and stock switch.  i
> dont *think* it would be a big deal, but i thought i would run it past
> everyone.  does this sound feasible?

I'm not sure of the specifics of those particular lights, but if the wattage
is the same as the stock ones, then I think you'll be OK reusing the factory
wiring.  However...

If the lights are a higher wattage than what you're pulling out, and you
don't change the wiring, then you're either looking at dim fog lights
because they can't get enough juice, of you'll melt the stock wires,
connectors, or relay that gives them juice.

If they're pulling more power, you should trace back to where the stock
switch feeds the stock relay, and use that to trigger the relay for the new
lights and wire them up with the new (presumably heavier duty) wires.

> i guess i worry about not using the supplied relay that is in the piaa wiring
> kit, although i cant figure out why i would need a relay to begin with..

The reason is the amount of current involved.  The fog light switch
activates a relay, this takes a very small amount of current.  The relay
then turns on the fog lights, using shorter runs of heavier cable, capable
of carrying a higher amount of current.  Since the longer the length of wire
used causes a larger voltage drop, you want higher wattage connections to be
as short as possible so that maximum power is available where it's needed,
which is the whole point of the relays.