Headlight relay harness construction tips

[Doyt W. Echelberger]

Scott Fisher asked for tips about building a relayed wiring harness for a
quad headlight conversion to e-code lights. This is what I learned, doing
that task. The story probably belongs on a web site, but I don't have one.
So, it is offered for the archives, with apologies to those who already
know how to build a harness, or who simply don't do that sort of thing or
don't care.

The easy way to build the harness is to use wire that has a minimal number
of strands of copper in its construction. Something from the rack at Ace
Hardware, in a 10-12 gauge size, which avoids the problems of using the
ultra-conductive stereo cable that is made up of hundreds of strands of
tiny copper wires. The Ace Hardware wire cuts and crimps much more easily
than the stereo cable stuff. I used the stereo cable because it was
available free from a friends scrap bin at his stereo cabling operation,
and he loaned me his tools and showed me how to use them.

In addition to the excellent information on the Stern web site
http://lighting.mbz.org/, I'll tell you the secret of working with the 8
and 10 gauge fine-strand stereo cable, in case you insist on torturing
yourself that way. Some of you might even want to cable your car stereo system.

Get/buy/borrow/rent a professional cable cutting and crimping tool. Looks
like a big sophisticated edition of your grandmother's toenail cutters.
About $40 from the Mack Tools guy who travels around to shops in a tool
truck. I borrowed one from a friend who makes his living cabling cars for
stereo systems.

Without this tool, you are going to hack away at the cable with some tin
snips or maybe a box cutter, and usually you will get a ragged frayed cut
of the fine multi-stranded butter soft copper filaments that make up the
cable. These frayed copper filaments are then almost impossible to twist
into a form that can be inserted into the open end of a crimp connector.

If you find a way to cleanly cut the cable, the secret to good crimps is to
use the first two fingers and thumb to gently shape and twist the cut
strands into a small compact shape that will cleanly slide into the open
end of the crimp connector, AND THEN AS YOU PUT ON THE CONNECTOR, YOU TURN
THE CONNECTOR IN THE SAME DIRECTION AS THE TWIST THAT YOU PUT INTO THE CUT
CABLE. Yes, I am shouting about this.  Doing it any other way balls up the
fine copper filaments and prevents part of the bundle from getting to the
crimp section of the connector. Then you apply the crimp tool, putting the
punching part on the OPPOSITE side of the cut in the crimp tube. This
forces the tube to collapse evenly on the contained copper strands,
pinching them firmly against each other and against the wall of the crimp
connector.

That is how my friend earns a living, day in and day out, working his life
away putting crimp connectors on stereo cables. His shop contracts with
local auto dealers to customize the new cars with fine stereo equipment. I
did it like he showed me, and it went smoothly, using his spare
cutting/crimping tool. The cable was free, and I got the connectors and
blocks at his cost. To build a quad light e-code headlight harness from
stock, you will be doing about 22 cuts and crimps plus 10 cuts that go into
the spring-loaded slots in the e-code connectors. 33 bungled cuts is a
nightmare. Get the tool or use wire with fewer strands.

An alternative is to buy a ready-made generic headlight harness, which I
have seen advertised (Blau?) but I never spent any time investigating. It
would save you about 4 hours of work with tools and materials that are
expensive and hard to acquire. It might be prudent to hire the work done by
a cable specialist, who could build your harness in about 45 minutes or less.

OK, end of sharing of secrets learned while cabling a quad headlight
harness. Apologies to those whose bandwidth is costly.

Doyt Echelberger
87 5ktq, with e-code quad lights from a 1985 5k.
On high beams, the road looks like it is being illuminated by the landing
lights of a747.  And even with low beams I can finally see the road.



 >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
At 10:26 AM 12/14/2001 -0800, you wrote:
................................snip..........................
>Anyway, once again, thanks for the detailed notes on how you wired your
>relays and lights.  Any tips on what kind of relay to get, or what kind of
>store to get them?  I'm clueless...

,,,,,,,,,,,,,,,,,,,,,,,,,,,start with Daniel Stern's web site
http://lighting.mbz.org/

and read everything. He has schematics and sells the materials. He is
located in Texas and is the premier lighting specialist for such
conversions.  He sells Hella relays, and if I were doing it over, I'd use
Bosch heavy duty 40 amp relays.

>--Scott Fisher
>   Tualatin, Oregon