Interesting Matt.

That explains why it was there. I figured one would just tap into
exsisting wiring w/o a need for this magic box. Not so.

Fortunately the lights already worked fine. Originally I had seen the
rats nest of wires and cleaned up a little then left it. When I
realized the side markers weren't working, then I removed the "magic
box" while doing the other work.

This begs a question. Or two. -- ;^)

I used shrink tubing and electrical tape to fix where PO had removed
casing to tap into wiring.

Is there a specific type of electrical tape that will withstand heat
generated in engine compartment?

Tape that was there was starting to unravel. I figure due to, in part, the heat.

Also, I used #14 wire to extend #20 (?) gauge that connects to side
marker light lamp bases. Some of the #20 wire casing was in poor
shape.

I know the light will draw what it draws, but is the use of larger
gauge wire going to cause any problems?

Regards,

Neil.

On 5/6/07, Matt Roberds <mattroberds@cox.net> wrote:
> > From:    neil <musomuso@GMAIL.COM>
> > Date:    Sat, 5 May 2007 11:37:57 -0700
> >
> > http://web.mac.com/tubaneil/iWeb/Site%205/Mystery%20part.html
>
> I know this part has already been identified and excised, but I figured
> I'd add a little...
>
> Most small trailers in the US and Canada have one lamp on each side that
> serves as both the turn signal and brake lamp.  Historically, most US
> cars had a similar arrangement for their rear lamps, so hooking up
> trailer lights was pretty simple - the left trailer lamp hooked to the
> same wire as the left rear car lamp, and the right trailer lamp hooked
> to the same wire as the right rear car lamp.
>
> Most European and Japanese cars, as well as more recent US cars, have
> two rear lamps on each side - one with a red lens for the brake lamp,
> and one with a yellow (usually) or red (sometimes) lens for the turn
> signal lamp.  You've got two wires on each side of the car, but only
> one wire on each side of the trailer.  You can't just hook all three
> wire ends together, because that would make the lamps on the car operate
> incorrectly.  Using two diodes would sort of work - the car lamps would
> operate correctly, but the trailer lamps would only flash with the car
> turn signals until you stepped on the brakes - then the trailer lamps
> would come on solid no matter what the turn signals on the car were
> doing.
>
> That box does the magic to make the trailer lamps behave correctly when
> connected to a car with separate rear turn and brake lamps.  They come
> in various flavors - some are a box with wires on both the "car" and
> "trailer" ends; some have wires on the "car" end and a built-in
> connector on the "trailer" end; some fancy ones have connectors to match
> the factory wiring harness on the "car" end and a built-in connector on
> the "trailer" end so they can be installed without any splicing at all.
>
> The "trailer" end of the wiring is usually (not always!) four wires:
> white (ground), brown (running lights), green (right turn/stop), and
> yellow (left turn/stop).  If you see a harness of white-brown-green-
> yellow or brown-green-yellow wires hanging out near the rear bumper of a
> car, it's quite often someone's attempt at a trailer wiring connection.
> You can usually get 14 and 16 gauge four-wire "ribbon cable" (four
> insulated wires bonded together) at the FLAPS.
>
> The "car" end of the wiring varies more, but on the converter boxes, a
> common configuration is five wires: white (ground), brown (running
> lights), green (right turn only), yellow (left turn only), red (stop).
> Some converter boxes omit the white (ground) wires on both the "car"
> and "trailer" sides, so there are only four wires on the "car" side and
> three on the "trailer" side.
>
> Mini rant: The ground wire is NOT OPTIONAL!  No, it won't ground through
> the hitch ball - at least not after you hit the first bump!  Both the
> trailer and the car need ground wires.  Even a wire that runs from the
> trailer half of the connector to a sheet metal screw on the trailer
> frame, and a wire that runs from the car half of the connector to a sheet
> metal screw into the car body, is better than hoping it will ground
> through the hitch ball.  The Syncro Deluxe version is to make the ground
> wire one or two gauges thicker than the other wires, and to replace the
> sheet metal screw with a bolt, flat washer, ring terminal, toothed washer,
> (car or trailer metal), flat washer, and self-locking nut in that order.
> Hitch-ball grounding and/or broken ground wires are the leading cause of
> flickering trailer lights.  End of mini rant.
>
> In general, one of the few things that will drive you crazier than DPO
> stereo wiring is DPO trailer wiring.  If you have a car, truck, or van
> that's new to you and the outside lights are acting weird, run, don't
> walk to the back of the car and inspect carefully for signs of trailer
> wiring.  This applies even if no sane person would attempt to tow a
> trailer with that kind of vehicle (i.e., Geo Metro or similar).  If
> there are strange wires dangling around that are connected to the rear
> lights, and you can't convince yourself that they are stock, get rid
> of them.  This can help your sanity immensely.
>
> Matt Roberds
>
>

--
Neil Nicholson. 1981 Air Cooled Westfalia.

http://web.mac.com/tubaneil