> My understanding is that the reason headlights were not fused
> in MGs was so that a blown fuse would not leave you without
> headlights at an inopportune moment.
That sounds like Lucas logic. I can just imagine the Lucas
engineers... "Okay mates, how do we want to play this, a
headlight failure or a melted wiring harness -- and a headlight
failure? Right. Oh ey? Either way, the prats are gonna bite
a tree. I say we go for the cheaper and easier total meltdown
plan! Right, grab your kit and let's nip off for a pint?"
:-P
> Wouldn't the same logic apply to a relay? Do "modern" cars
> have a relay in the headlight circuit?
My German and Italian cars do. In the newer BMWs, the whole
thing is computer controlled. No, it's not a Microsoft system.
Thank God!
> Since I plan to completely rewire my 74 1/2 GT I would
> appreciate comments from those more knowledgeable.
Can't make a statement as to the "more knowledgeable" bit
but I will share ideas and opinions.
Bill, we are building a historic rally car using a '68 BMW
1600-2 as the starting point. I have built much of the electrical
system already. In that car, we are using high output, high current
lighting WITH relays and fuses. That has three immediate
advantages;
(1) The high current does not have to run long distances
(read: resistive circuit)
(2) The switching circuitry needs only to be rated for
"control voltage" (read: low current).
(3) No large gauge, high current wiring is in the cockpit.
Better put, the switches in the cockpit activate the headlight
(and horn and cooling fan and ...) relays only. Those relays are
on a circuit panel on the left front fender well right behind the
radiator bulkhead. That makes the run to each headlight no
more than about a meter. Each of the three headlight circuits
(high beam, low beam and driving lights) is fused right where
it leaves the circuit panel. The control voltage is also fused in
the cockpit but is on an independent circuit <with only other
relays>.
FWIW, in the rally world, the 'low beams' are called 'ditch
lights', the high beams are 'pilot lights' and the driving lights
are, well, driving lights. :-)
If you wish further details, circuits, formulas for current,
wire gauge, etc., just drop a line. I hope this helps...
rick
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