H4 wiring harness upgrade

[NightKids]

Hey guys, I've currently got some Philips X-Tremes in my car (H4). I was hoping to make them brighter or even run some higher wattage bulbs. I heard that upgrading the wiring can make them brighter. Is this true? And what wiring do you recommend and where do I purchase it from? Cheers...

[vinnY]

pretty hard to come by i think
can easily make one yourself as long as you know how to crimp wires and solder a bit

general bits you need

2xrelays
2xrelay plugs
2xfemale h4 plugs
1xmale h4 plug
10-15m of 12ga cable(use 8ga if you like)
2xfuse holders
2xfuses if your choice

made one myself, never bothered to put them in though, not worth the trouble at this point

[NightKids]

Oh yeah i remember reading a few threads that you're actually quite good at this. So you didn't even put it in? From what I recall you made one yourself...

Wouldn't it be possible to just stick one of these wire plugs on?

http://www.eautoworks.com/product-Ca...hine-23760.htm

[vinnY]

you can, it would just melt the rest of the wiring or blow all the fuses
they seem to be just female h4 plugs with 16ga wiring attached.. nothing else

[NightKids]

Oh damn that's annoying. So how much did it cost you for all those parts? And is there any kits that have what you mentioned for sale as a package?

[vinnY]

there are kits, just not in australia as far as i know
wouldn't really have spent more than 80odd bucks to make the harness

[dahondr98]

Oh damn that's annoying. So how much did it cost you for all those parts? And is there any kits that have what you mentioned for sale as a package?

Yes, there are. Contrary to what Vinny said, they are easy to get hold of (sorry Vinny!). The two main looms available in Australia are made by Piranha and ARB, who both supply parts for 4WD's. I've got the Piranha kit in my Civic, and it makes quite a difference. I did just get a price list from ARB recently (I'm a shareholder, so was checking their products!), and their wiring loom costs about $150 - I can't confirm the exact cost, as I suffered a PC crash soon after they sent me their price list, and I lost it when re-formatting my hard drive. The Piranha kit uses 6mm wire, which apparently is slightly thicker than the ARB loom, and I think they cost about $200.

The ARB looms are available at any ARB 4WD store, and the Piranha loom is available from plenty of 4WD accessories stores, such as TJM, Opposite Lock, 4WD Warehouse, etc. Either will be better than the thin wiring Honda uses as standard. Another seller of upgrade looms on Ebay is Hobzee's 4H 4WD Shop - see http://cgi.ebay.com.au/Nissan-Patrol...item33565dc2ed , or at http://www.4h.com.au/prod358.htm . As he says on Ebay, although it's advertised for the Nissan Patrol, it will fit most other cars - he uses 6mm wire for high beam and 4mm wire for low beam - Honda use inadequate 2.5mm wire. I did see recently on a 4WD forum that there is a 4WD shop in Melbourne that has identical Landcruisers, with the only difference being a Piranha loom, and apparently the difference in light output between them can be seen easily - apparently most people spend the money to buy the loom when they see the difference! Most Jap cars use the same thin wire, whch is why Nissans and Toyotas also benefit, like Hondas.

From tests I did when my Civic was new, the voltage drop was about 15% at the headlights (more than 2V drop), and according to Hella, that equates to the headlights only being 54% as bright as when they have full battery voltage. I can certainly confirm, from swapping the plugs between the aftermarket Piranha loom, and the original loom, that the aftermarket loom gives much brighter light, on both low and high beam.

If you want to build one yourself, you can get all the parts from NA Auto, who supply auto electrical parts online - see http://www.naauto.biz . Unfortunately they have had someone redesign their online shop using Javascript, so it takes a long time to load, and doesn't work unless you enable Javascript. Get rid of it, NAAuto! You can certainly save some money by doing it yourself, but it is a bit of work.

Finally, if the EG headlights have plastic lenses, don't use higher wattage globes - you'll wreck the lights very quickly. If they are glass lights, then you can use higher rated globes (eg 80/100W), but you need to upgrade the wiring to handle the current. Better to do that first - most likely you won't bother changing the globes - the Philips globes are the best available at present in standard wattage.

[PlatinumVisuals]

Don,

Weren't the AUDM headlights made out of glass ? And the JDM Headlights made out of plastic ?

Edit:

I just noticed you said "if" My mistake.

[dahondr98]

Don,

Weren't the AUDM headlights made out of glass ? And the JDM Headlights made out of plastic ?

Edit:

I just noticed you said "if" My mistake.

Yeah, as I don't own that model, I didn't know.

[mocchi]

i still dont quite understand where to plug them.

we rip out the old harness?

[vinnY]

you plug them into your old harness as they switch the bulbs off/low/high

but they are now powered by the new wiring

[dahondr98]

i still dont quite understand where to plug them.

we rip out the old harness?

Yes, a Vinny said (I wasn't near a PC yesterday, as I wasn't at home), you plug the new harness into the old one. You don't rip out the old wires - they are still needed to power the new relays.

Specifically, you have a lead to the battery positive, a plug to plug into the old harness, two new sockets to plug into the headlight globes, and usually two new thick earth wires, one for each headlight socket. You unplug the old headlight sockets, attached to the Honda original equipment wires, and plug one of them into a male plug on the new harness. That gets the power from the old Honda wiring, to switch the relays on the new harness, for low beam and high beam. Then, the new harness has sockets which plug into your headlights. Put the earth wires to handy bolts in the engine bay near the headlights, to earth the non-battery sides of the headlight globes. That's it. Plug it in, attach several wires to battery and earth, mount the relays in a spot in the engine bay between the battery and closest headlight, and you're done.

Because the wires are nice and thick, and are all in the engine bay, the voltage drop is much less. The Honda wiring, while being much thinner, also travels from battery into the cabin of the car, via the headlight switch and dimmer stalk, back into the engine bay, and then to the headlights. It travels much further, and it's much thinner, so the old wiring drops a lot of voltage. The new wiring is much shorter, and much thicker, so is much more efficient. The old wiring is still needed to switch the relay coils, which only take a tiny amount of current, so the load is reduced on the old wires, and on the cabin headlight switch and dimmer switch.