Headlight Relay Circuit, lowest resistance, low components

[ciper]

I had the task of designing a circuit that:

Did not modify the vehicle in any way
Produced the lowest resistance to the lights
Used the minimum amount of components
Lowest cost

I have now a tested design that has two function, one being the normal operation of high lamps on when high is selected, low when low selected in normal mode. In secondary mode the low is on when low is selected and both are on when high is selected (GREAT for flashing to pass). Both of these modes also allow the lamps to shut off when the switch is off.

Now you may say this sounds very simple. You are way wrong. I had 4 of my coworkers working on circuit designs. Every time there was a failure. If you'd like download a FREE "Electronics Workbench" clone from http://www.microcode.com/downloads/student.htm

Its supposed to be for students..

Anyways I have a bitmap if someone can host it for me.

The required components are:
Two headlight harness, bulb side(junk yard, many old bulbs)
Two headlight connector, car side(junk yard, cut from another car)
Relays, BGMICRO has some prewired with harness and fuse for 2.95 each that are 40 amp spdt that work perfect, 5 or 6
A single switch (to enable/disable the other mode)

I just realized I should probably check the vehicle for how it triggers the lamps. I assumed the lamp always gets a + and the seperate filaments are activated by ground them out. If this is not the case I will need to modifiy my circuit.

If someone can host the image that would be cool. Its only 25k and color.

This circuit would also be perfect for those of you who want to run 9007 bulbs.

[Legacy777]

shoot the image over to me.

as far as bulbs......we run the 9004 bulbs right? Are the 9007's better.

I've got new headlights that are not yellow'd all to hell to put in when I get my turbo hood and such......I was goin to rewire the lights with relays directly to the battery.....but if I can get better lights......I'd be interested.....

I just haven't done a lot of research on what's out there and will work.....

[IggDawg]

I'm pretty sure we're running 9003s like the pre-GDA imprezas.

[entirelyturbo]

We use 9004's. I just replaced my stock ones with some Hyper Whites not long ago. I also understand that 9007 will not interchange with 9004's.

BTW, someone told me that our plastic connectors would begin to melt if we put too much wattage through them (The stockers are 65Whigh/45Wlow, I have 100Whigh/80Wlow in there now, it's illegal, I know ). But I keep checking mine and I am seeing no such thing. Anyone else heard this?

[Legacy777]

I've been runnin 80/100w bulbs for almost 7 years now.....same bulbs!!!

I've heard of it happening.....however I've had no such issues.