Installing Driving Lights

[tonysrich]

I'm having a go installing a set of driving lights by myself. I'm making my own wiring loom, it's pretty easy to do but I have one small problem. I'm not sure where to conect the wire from the relay, the low voltage one that switches the relay on.

Can anyone help me please.

[Hunno]

Tony,

Legally your driving lights should only be able to work with your High Beam.
So you need to pick up your supply from your high beam circiut,
then to your on/off swicth,
then to the coil of your relay.
Hope this helps

[tonysrich]

Thank you for your reply
I already understand conceptually how the lights need to be wired up but what I'm not sure of is where abouts I should pick up the high beam circuit
I think that I could connect the relay to the high beam wire at the head light plug but I'm not sure if this is the right way to do it

[Hunno]

that's the way I always done it. But only through ease of access.

[Rob&Tanya]

Hi I have wired mine the other way
from high beam wire to relay and ran the earth/neg to the switch in car

much easier
cheers rob

[Hunno]

it doesn't really matter where the switch is in the relay coil circuit. It only job it to make a break in the circuit so the coil is is not always energised. Having said that if you have a short in the wire after the coil the lights will always be on,

[glend]

You need to watch the rating of the relay in the various kits on the market, as many of them are only rated for 30amps. If you upgrade the wiring loom feed to the driving lights they can carry so much current that (momentarily) they can fuse the relay together and lock the circuit on; this happened to me with my Narva Combo kit and I had to pull the fuse to disable it. A 70amp relay is a better choice just from the contact area point of view (meaning they can handle more current without heating up so much they fuse the small contact surface area).

Re the relay coil circuit wiring, I used the high beam power feed to the driver side headlight and just tapped it into the wire with a splice tap and taped it up with electrical tape. I run the high beam trigger wire through a switch on the dash (so that I can turn the driving lights on or off when the high beams are on, but not when the high beams are off). The other side of the coil is earthed. The current draw of the coil circuit is so low that it will have no effect on the high beam light output.

In some situations (like say you were using a reverse light signal to trigger an auxilliary backup light relay coil ) where the reversing lights are powered from solid state components as opposed to a old fashion reverse selector switch; its a good idea to use a diode across the coil supply to avoid spiking back into the cirucit when the coil collapses, but this is usually not an issue with driving lights. These coil collapsing currents can feedback into the solid state components and cause failure (a particular problem with vehicles with 545RFE transmissions that use a low voltage reversing light signal from the transmission electronic pack to feed the reversing lights).