I could have also named this thread just the same as the image I've drawn - "Universal Driving Light Wiring". It's basically a how-to wire up your driving lights no matter what method the manufacturer used to make your headlights work. It works because the globes MUST have power running through them in a particular way.
I've just done this exact mod on my wife's car, which doesn't have earthed headlights - the car's light controller governs whether or not one pin or the other on the headlight is powered or earthed.
However, it does have ONE thing it will ALWAY and MUST do: the common wire must ALWAYS be opposite to the LOW or HIGH beam wires.
This makes the task of bringing driving lights on rather easy, but you can't turn them off independently ... wait, yes you can!
The attached (basic) diagram shows how to do it. Items required:
2x 30A relays (or more, see note below)
1x 20A fuse (see note below)
1x H4 headlight socket extension (example here)
1x 10A rocker switch
Electrical connectors and cable in red, black, blue and green
The fuse should be slightly higher than the total amps drawn by the lights, 20A is for a pair of 100W driving lights = 2x8.33A = 16.6A. A 500W light bar would draw 500/12 = 41A so use a 50A fuse and don't let the car idle for long with that much juice being sucked from the battery!
The relay powering the lights (relay 2 in the diagram) needs to be rated much higher than the lights. Relay 1 is really only triggering the other relay so it can be anything you have handy.
Ok, explaining how it works: you're connecting a switch to an earth point in the cabin and running the other side of the switch out to the engine bay onto relay 2. When relay 1 is on and feeding positive power to one side of relay 2, switching this switch on will activate relay 2 allowing power to flow from the battery to the driving light(s) and on they come.
Relay 1 activates whenever high beam is on. The H4 extension is used so that you can solder-tap into the wires between and make it a really neat job that's removable if you wish - just take the extension out and fit to your new vehicle.
This circuit will also work in a "old style" headlight system as well.
See the attached diagram and enjoy.
I've just done this exact mod on my wife's car, which doesn't have earthed headlights - the car's light controller governs whether or not one pin or the other on the headlight is powered or earthed.
However, it does have ONE thing it will ALWAY and MUST do: the common wire must ALWAYS be opposite to the LOW or HIGH beam wires.
This makes the task of bringing driving lights on rather easy, but you can't turn them off independently ... wait, yes you can!
The attached (basic) diagram shows how to do it. Items required:
2x 30A relays (or more, see note below)
1x 20A fuse (see note below)
1x H4 headlight socket extension (example here)
1x 10A rocker switch
Electrical connectors and cable in red, black, blue and green
The fuse should be slightly higher than the total amps drawn by the lights, 20A is for a pair of 100W driving lights = 2x8.33A = 16.6A. A 500W light bar would draw 500/12 = 41A so use a 50A fuse and don't let the car idle for long with that much juice being sucked from the battery!
The relay powering the lights (relay 2 in the diagram) needs to be rated much higher than the lights. Relay 1 is really only triggering the other relay so it can be anything you have handy.
Ok, explaining how it works: you're connecting a switch to an earth point in the cabin and running the other side of the switch out to the engine bay onto relay 2. When relay 1 is on and feeding positive power to one side of relay 2, switching this switch on will activate relay 2 allowing power to flow from the battery to the driving light(s) and on they come.
Relay 1 activates whenever high beam is on. The H4 extension is used so that you can solder-tap into the wires between and make it a really neat job that's removable if you wish - just take the extension out and fit to your new vehicle.
This circuit will also work in a "old style" headlight system as well.
See the attached diagram and enjoy.
