Thread: PROJECT 2, Headlight wiring up grade

Hi folks, the wiring diagram above is for a generic headlight wiring loom up grade and will work for both positive and negative switched headlight systems.

If the new loom is made to the diagram’s set up and connections made to the vehicle’s existing headlight sockets, then there will be no need to cut into or alter the vehicle’s wiring in any way.

Once the new loom is installed, the vehicles headlight globes will now be positive switch no matter what polarity the vehicle’s headlight switch work by.

The reason for using 4 single pole relays instead of 2 double poled headlight relay is to increase safety. If standard double poled headlight relays are used and a fuse blows or a relay fails, you can loose either both low beam or both high beam at the same time.
By using 4 single pole relays, if a fuse blows, you will only loose 1 high beam AND 1 low beam, or if a relay fails you will only loose either 1 high beam OR 1 low beam.
This is a much safer way to operate the headlights.

The 4mm2 Automative wire is way above what is needed but by using the heavier cable, and by running an earth wire from the headlight globe all the way to the battery, the standard headlights should be brighter and slightly whiter.

With this set up, the relays are protected by the vehicle’s existing headlight fuse but the current that is required to operate the headlights via the vehicle’s headlight switch is now about 1/50th of what was needed before the new loom was installed and this should considerably extend the operating life of the vehicles headlight switch.

Once all the wiring is in place and the lights have been tested, all the new cable should be protected by housing it in split tube and securing the tube by way of wire tires.

Pictures will follow.

Once the new loom is installed, adding a driving light up grade loom will be a simple chore but this will be another project.

Cheers.

I finished this upgrade on the weekend and last night i drove to the drive in theatre out yatala and home again and the increase in light from my original is absolutely un beleivable easy around 150% better lighting (i can actually see the road at night now)

Ill be doin the driving light add on very soon aswell

Thanks drivesafe it an orsum article [img]style_emoticons/<#EMO_DIR#>/biggrin.gif[/img]


Cheers
Anthony

We had this diagram do the rounds at work today of their forums.

Hi George130 what was the outcome.

Cheers

Hi Grimace, glad to hear that you got some benefit from the project.

I hope to get some time in the not to distant future to add a bit more detail and pictures to both the Headlight and Driving Light Projects.

If you have any pictures or more importantly if you can add any ideas to help improve the projects please do so.

Cheers.

It was posted in reply to toyota owner wanting to upgrade his lights. He is doing it this weekend. Others have since replied that they used the same setup but with oly two relays. Overall consensus was that this was the way to go as you should only ever lose one light when relays died.

Hi George130, yes it is a bit messy using 4 relays but for the very reason you mentioned, with the 4 relay set up, if a relay or a fuse goes west, you are still left with 1 light and not in the dark as is the case when using just 2 relays.

Cheers .

PS I will be marketing a generic kit with all wire ( heavy duty for the actual headlight wire ), relays, fuse holder and fuses, crimp terminals, standard headlight sockets ( pre wired ) and split tube for about $70.

Tim, what software do you use for the drawings? Are the relay symbols, etc., already in the software library?

Ron