Is back feeding 12 volts an issue?

[Scootsk]

Hi All

Hooking up some smiley on a 1990 E30 Covertible. This is a conversion from the sealed beams. I would like to have both the low beam and high beam on when the high beams are engaged. I will be putting in a relay to send 12 volts to the power leg of the low beams when the high beams are engaged. Will this cause any issue that you know of? I'm thinking that it won"t, since its a simple switch rather than going through an electronic module.

Thoughts?

[earthwormjim]

Are you sure your low beams turn off when you engage the high beams? That's not how my car works, although it is a Euro model. Looking through the ETMs online, I see no reason why the low beams would turn off though.

It's the fog lights which are disengaged normally. See ETM: http://www.armchair.mb.ca/~dave/BMW/e30/e30_92.pdf

The light relays are open or floating when in the "off" position, so it should be OK to backfeed if in fact your low beams turn off.

Just confirming what you wrote, you intend to have an independent source as the backfeed, you're not using the high beam wiring to simultaneously power the low beams right? Hence your relay?

[Scootsk]

thanks For answering. I think I’m going to use a diode so the voltage can’t reverse to the switch. Better safe than sorry.

[Mo Brighta]

Smiley operation

I have designed a relay modification that revises the relay logic, to do just what you are looking for. It still uses the low and high beam relays, just does this when you want. $13, screwdriver simple install.


I'm building several of these, did you want one?


Andy