I've been thinking about rewiring my lights... mine are as Land Rover did them and have never been removed or disconnected. The problem is that the wires do not all fit beneath the trim at the side of the windscreen - the trim bulges and you can see the yellow wiring beneath.
Because there is never any need to operate each set of lights independently the only wiring I think is needed is an earth and a live. I'll then put a junction on the roof rack to distribute to the four units up there. This has the added bonus that I'll then be able to consolodate on the three sets of relays under the hood.
A voltage drop of 0.5V is acceptable (in my book) and I'll research the guage of wire necessary to meet the current requirements.
One thing about my lights is that the wiring loom does not support the dual beam function. The lights have it, but there is nothing in the loom that Land Rover put in.
I may look to acquiring a control box to see if this can give me that functionality - the switch has had the mode button rather crudely disabled by desoldering the micro switch beneath so I'll need to replace or repair this too. I have no idea why this has been done but assume that in doing so there is no way of accidentally swithing mode and thus turning the lights off.
If anyone knows if the control boxes are available or whether they have a part number from either Warn or Land Rover I'd be grateful for a note. _____________________2005 G4 Discovery
2006 D3 Thailand Media Vehicle Stages 1 & 2
2004 D2 Landmark Auto (much missed already!)
that would work - 99% of this sort of job is routing the cabling - if you can find a convenient route and gain the same functionality then I think it is a good idea.
I don't know what power rating the lights are but I'm guessing at 60W a piece. 240W in total and that over 12V gives just 20amps. So your 100A supply would be more than adequate.
I found this site for calculating the wire guage: http://www.powerstream.com/Wire_Size.htm but it is american and all measurements are in horse strides, half straw bale weight, and coconut shells or what ever it is they use.
I think I concluded that 4AWG (5mm diameter core) cabling would suffice based on 24ft of cable (crudely calculated on 6ft across the engine bay and 6ft up to the rack and then all the way back to the battery). This gives around 0.3V drop across the circuit based on a 12V supply.
Because I have made many assumptions I would strongly recommend checking with someone who can instinctively say what guage to use!
Something I have just realised is that in wiring all lamps through one relay / circuit you have no built in redundancy - if one faulty fuse, relay or cable will put all your aux lights out. _____________________2005 G4 Discovery
Looking in the loom to get the dual beam function, you need to check that the tiny Blue wire from the power/mode switch is connected to the main lighting loom otherwise the dual beam does not function. By fitting a power/mode switch in lieu of the power switch later vehicles can be provided with the 2 lighting modes. The lights should all be fitted up to work with both modes.
Lights can be made to come on with either sidelights, dip or main beam by selecting which is the feed source. So if as in Mark's case the lights only come on with main beam remove the feed from main and attach to dip etc.
Adrian