[TR] TR3 Headlamp Upgrade

[Randall]

>      What is the best headlamp upgrade where I don't have to 
> make a new wiring harness?

First, punt the stock tungsten sealed beams and install a pair of
quartz-halogen bulbs.

Then if you want to keep all original wiring, go over it with a voltmeter
while the headlights are on, and make sure they are getting every last volt.
Chances are that the wires themselves are fine, it's the connections that
typically develop some resistance and limit current/voltage delivered to the
bulbs.

>      What are other listers happy with?

On my previous car, I used a purpose-made relay (actually two relays in a
metal box), screwed to the firewall.  The original high/low beam wires were
re-routed to the box, and new wires added to bring power to the box and
carry it to all 4 headlight beams.  I also used 60/100 watt H4 bulbs (and
had a 60 amp alternator to back them up).  Those high beams would light up
the night like you wouldn't believe!  The relay box is visible in this (old)
shot:
http://tinyurl.com/2336n5v

The only problems were all the exposed wires (which didn't bother me at the
time, but might bother you); and the fact that the relay box incorporated a
single fuse for each relay.  Coming down a mountain road into Durango, CO on
a moonless night, driving rather too fast for conditions (as I frequently
do), the fuse popped!  Fortunately, all I had to do was think to hit the
high beam switch to get some lights back, but it was definitely a
heart-stopping moment.

So this time around, I am using a separate relay for each filament, and a
separate circuit breaker for each side (so if a CB pops, there will still be
a headlight working).  To reduce the number of new wires visible, I am
mounting the relays to the back of the headlight bucket:
http://tinyurl.com/3yzdl9b
This results in only one new wire to each headlight from the circuit
breakers (which I think I will mount under the dash, out of sight).
Although they really should have tracers of some sort, purple is the correct
color code for a protected (fused) wire that is always hot and I just happen
to have a roll of purple 12 AWG "machine tool" wire.

(Using the relay sockets was a bad idea; awkward to wire and you can see
where I managed to partially melt one while setting the heat shrink tubing.
Next time I'll just use individual quick connects.)

Randall