Thread: HOW TO: Keep low-beams on with high-beams (2-bulb style headlights)

Spread the joy! My write-up-for-newbs on keeping your lows on with highs on a 2-bulb headlight.

!!This is only for 2-bulb systems, one bulb for low-beams and one bulb for high-beams. This is not for stock or single-bulb systems!!

To get your lows to stay on when you switch on the highs, you need to add a standard Bosch-type relay as shown below:



Two things to remember here:

1)+12V means exactly that, go right to the battery with a fused line. This gives you a good power source for the lights.
2)Use a relay capable of the power for both low-beam bulbs. Anything lower and the relay will overheat and fail.

Leave 87a unused as nothing is being changed with the highs off. Just cap it off, and install the relay somewhere nice, unless you want something to turn on when your highs go off. Then hook that nugget-o-joy up to the 87a terminal. It will turn off when the highs are on, and remain on at all other times.

EDIT: Thinking this over a bit, and looking at my diagrams, there's another way to do this. The trick is you need a diode that can handle the power of your headlights with little to no loss or pass. Here's how it'd look if you went diode.



PM or post with questions, either way will work for this mod.