Thanks Steve for your advice.

 

I haven't think about gauge size of the wire. Do you think I should run 10G wire up to relay? or all the way upto headlight?

 

I found some interesting site.

https://www.tessco.com/yts/industry/products/itm/automotive/get_wired.html

14 AWG is quite adequate. A 10 foot run of 14 AWG to the headlights would have a voltage drop of about 0.25VDC. Going up to 10 AWG gives you a drop of 0.100VDC.

Simplified version schematic.

 

one 30A fuse version.

 

two 10A fuse version.

Found good size relay box from Junkyard Toyota car.

From my schematic, I can just modify wiring within Engine bay.

 

 

It fits 3 relays and 1 30A fuse.

I can use 2 relays and 1 fuse for headlights and another relay for something else :-) Maybe radiator fan?

Edited May 28, 201511 yr by tamo3

Good find. What car and year?

I forgot what year, but it's from Camry

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Before I finished up my relay upgrade, I was also looking for a pre-existing box to house the relays and some fuses.

 

Here's the best one I could come up with.  It's a pretty adaptable relay/fuse box from (I think) the later model of Corolla. I like it because not only does it have room for four relays, but it also has four of the mini blade fuses. This is the only pic I have handy right now:

 

I'll try to snap a couple better pics of the box with the lid.

 

Captain, 

You scored good one! I saw a lots of Camry at junkyard, but not much Corolla. That's nice one!

I have some of these sitting in my garage:

http://www.amazon.com/gp/product/B000VUEDXY?psc=1&redirect=true&ref_=oh_aui_search_detailpage

http://www.amazon.com/gp/product/B000VUASBK?psc=1&redirect=true&ref_=oh_aui_search_detailpage

 

They are a similar form factor to those relays.

You scored good one! I saw a lots of Camry at junkyard, but not much Corolla.

 

Tamo, It's yours if you want it. I'll send it to you if you would like.

 

I'm not going to use it now that I've got my headlight relays mounted using a different scheme.

Found good size relay box from Junkyard Toyota car.

From my schematic, I can just modify wiring within Engine bay.

 

IMG_8303.jpg

 

It fits 3 relays and 1 30A fuse.

 

Hi Tamo,

 

Looks like it will make a nice clean setup when you finish. Be sure to take some photos when you fit it.

 

My headlights have been changed to meat european regulations and the PO upgraded to H4 with 60/55Watts bulbs. The original system uses 50/40Watts. I would like to do something like this to protect the combination switch now the system is using 20% more energy in high beam..

 

I have one small issue: The system will work on just one fuse. That means if it blows you will have no lights.

Could you double the relay bank for a left and right system. That way if a fuse should blow you will only loose the left or right (Hi and low beam) headlight. It would mean you will have two reserve relays for fog lights and fan etc.

I do a lot of HAZOPS, RCFA and FMEA where I work and its second nature to prepare for the worst.

Hi Chas,

 

I was looking at Captains 4 relays schematics.

http://www.classiczcars.com/topic/51554-a-different-headlight-relay-upgrade-4-relays/?p=470544

 

However, your requirement is to have 4 fuses too.

 

So, I modify my schematics for you with just for fun:-)

 

I also replace with H4 headlight, but I'm not so much worry about safety issue since I'm not planning to drive at night...!