Size of the headlamp wiring...

Batteries, Alternator, Wiring, Lighting, etc. (Please discuss ignition problems in the Engine category)
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Size of the headlamp wiring...

#1 Post by JimB » Tue May 01, 2018 9:01 pm

Hi there,

Does anyone happen to know the size of the headlamp wiring, the red/blue and blue/white cables from the master light switch to the headlamps? I assume it'll be AWG, not mm2.

I'm asking since I've got to cut into the harness/loom near the front wing, so I can put relays in - I've upgraded to halogens.

Thanks :D

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Re: Size of the headlamp wiring...

#2 Post by tony » Wed May 02, 2018 2:34 am

Not too sure it matters in your case. Since you're fitting relays the original wires are only going to be used to work the relays.
I fitted heavier cable from battery to relay and from relay to lamps to cut down voltage drop. Also make sure the earth wires from the lamp fittings are bigger to take the increased load. I have brilliant lights with halogens this way.
1976 2500 TC. converted to S specs.

Lots of bits

1999 BMW Z3.
2006 BMW 325ti.
Hopefully not needing too many bits.
1998 Rover 600


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Re: Size of the headlamp wiring...

#3 Post by Alec » Thu May 03, 2018 8:49 am

Hello Jim,

I use a company called Vehicle Wiring products for all my electrical bits and bobs.

Their website has useful information about relays and also cable sizes and what applications apply to what wire size. With headlights it is worth going up a cable size from recommended. Their cable is sold by the metre so you can buy the correct colours in the length you neeed.


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Jaguar MK 2 (Long term restoration.)
Hymer 564 Motorhome.

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