old headlights with new wiring

asap01 said:

I moved everything (wiring harness, engine, trans, axles, computers, steering wheel, pedals, etc.) from a 2003 GT to a 1951 F1 Ford truck.

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Interesting project...

I cut the Mustang wiring at the headlight bulb and ran 3 feet of 18 gauge wire to the old single hi/low sealed beam headlights. (The 3 feet extra was because we tipped the hood). The Mustang wire size was much smaller than the wires at the old F1 sealed beam three prong plug. Will the sealed beams and extra wire burn my Mustang fuse? What is the amps of the old sealed beam, Halogen, and the new lens with H4 replaceable bulbs I see on the internet? Thanks

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I can't tell you the power consumed by the OE F1 headlights but typically automotive H4 halogens are typically in the 55-60W range, which equates to about 3.9 to 4.2 amps at 14.2V. To be honest, although 18AWG is probably fine in practice, I think it's a little on the thin side for continuous currents of this scale for chassis power distribution. I would probably go to a 16- or even a 14AWG for the added safety factor.

It might be preferable to install a power relay that is switched by the small-gauge wiring and which delivers power to the headlights via the larger 16- or 14-AWG wiring.