Headlight Wiring Upgrade Step by Step Guide

[mybo Member Find all posts View Profile Close mybo]

Actually come to think of it, every circuit I've previously seen for upgrading headlight harnesses (whether positive or negative switched) has used only the one fuse, or at best (in the case of positive-switched applications) has individually fused the relays used for low beam and high beam. So with all of those circuits, if a fuse blows, you either have no headlights, or only low beam or high beam.
Good pickup Joel.

[Burrows75 Junior Member Find all posts View Profile Close Burrows75]

bansheebuzz is my brother, he should know this back the front as he is a auto electrician. You can use a circuit breaker so the system can be reset if there was some kind of failure.

[mybo Member Find all posts View Profile Close mybo]

Great! Can you please pass on my thanks to him? The circuit is great

[merado Lurker Find all posts View Profile Close merado]

is it just me or the pictures are very low resolution ? i can't make anything out.

[mybo Member Find all posts View Profile Close mybo]

is it just me or the pictures are very low resolution ? i can't make anything out.

Have you clicked on them? They open up in a new window in larger size.

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

Although upgrading the wiring seems like a good idea one should keep in mind that headlight bulbs are designed to allow for some drop in the vehicles wiring and you should keep in mind the following especially if your intending to install power bulbs:

The European standard for this is 13.2V, as little as as a 5% increase above the recommended operating voltage can cause a significant reduction in bulb life, ie one manufacture I have looked at in the past specified a 5% increase would result in a reduction of headlight bulb life of around 50%!

Cheers
Leigh

[bansheebuzz Lurker Find all posts View Profile Close bansheebuzz]

Thanks Mybo

I did write this in particular to the toyota surf/hilux/4runners of the 90's where typically would only get around 11.5 volts to the headlights. You should also note that i stated it will allow higher wattage globes, but this is not the case in the prados as they have poly-carbonate lenses and i do not recommend increasing globe wattage with this type lens.

I have never done a voltage check on a prado to see if the voltage is up to standard at the headlights or not. I can easily check as i have a 120 prado. In regards to the previous post. even by the time it gets through the relays etc you will be lucky to achieve 13.5 volts at the headlight globe and any d4d owners have nothing to worry about as the charge rate is about 13.3 at the battery anyway. I have run relays on my kun26 hilux d4d for many years now. i have my headlights set to come on with ignition so i have them on day or night and cannot remember the last globe i changed.

You can split it with 2 fuses if you like, however if it is all done correctly you will never blow a fuse

[bansheebuzz Lurker Find all posts View Profile Close bansheebuzz]

just did a quick check on a prado i forgot i actually had here at work. 120series v6 With 13.6 volts across the battery i am getting 12.8 volts across the high beam. Our industry standard states the we should have below .5 voltage drop on a circuit however at .8 volt drop i feel the gain would be minimal and not justified as far as light output is concerned. However by doing so you will be taking all the load of the existing headlight switches and prolonging their life

[mybo Member Find all posts View Profile Close mybo]

Good to hear from you bansheebuzz!

I didn't check the voltage drop on mine before going ahead with this. It was more of a 'piece-of-mind' project in any case. And I agree that its not a great idea to increase the globe wattage in this case. The Philips Xtreme globes I have are standard wattage

[Cookie120 Junior Member Find all posts View Profile Close Cookie120]

Although upgrading the wiring seems like a good idea one should keep in mind that headlight bulbs are designed to allow for some drop in the vehicles wiring and you should keep in mind the following especially if your intending to install power bulbs:

The European standard for this is 13.2V, as little as as a 5% increase above the recommended operating voltage can cause a significant reduction in bulb life, ie one manufacture I have looked at in the past specified a 5% increase would result in a reduction of headlight bulb life of around 50%!

Cheers
Leigh

I have had a lot of discussion on this issue with my auto elecy brother and you are spot on LeighW the volts at the lamp is the thing to look out for ( too high reduces life).. Typically Toyota have saved copper costs by reducing wire gauge and compensating through a higher alternator output voltage..therefore upgrade the wiring and you risk a voltage at the lamp that is detrimental to lamp life

[Razorback81 Advanced Member Find all posts View Profile Close Razorback81]

a question on modifying the way the light operate

i fitted a pair of angel eye lights, they have a parabolic light for low beam (H7) and a separate light for high beam (H1)
when you switch to high is there any way to have the low beam stay on?

my 2008 subaru has those type of lights factory and the low beam stays on when the high beam is switched on

any thoughts??

[scales82 Junior Member Find all posts View Profile Close scales82]

pictures are super duper low res for me too.

tried on tablet and PC.
Great writeup, keen to do this myself

[OlsensToursandTraining Junior Member Find all posts View Profile Close OlsensToursandTraining]

Anyone got a drawing of this circuit?