BY RON NEWTON
A friend of mine needed help
solving a problem his local
construction firm was having
with his big gravel trailers and
water tankers. His employees
kept breaking the taillights
and/or ripping out the towing
harnesses. This caused a sizable
amount of down time and
expense due to repairs. As you
know, it is illegal to tow without
taillights, and my friend’s rigs
are big. It is a disaster waiting
to happen if wiring harnesses
are being flexed too much.
LEDS draw small amounts of energy and can be powered using small batteries for long periods of time.
That makes them ideal for this type of project.
The unit presented here can be installed in minutes
and can also be carried for emergency taillights in the
event the wires are ripped from the trailer.
This project does involve a small amount of surface
soldering and chassis drilling. A Microchip programmer is
a plus, however, programmed chips and the PCBs are
available from the Nuts & Volts webstore. (I highly
recommend ordering these boards directly from NV.)
The board files are also on the Nuts & Volts website
( www.nutsvolts.com). You will need to cut the board
(a shear works best). The cost of the parts is about $80
in addition to the boards. This may sound a little on the
expensive side, but considering the cost and installation of
wired taillights — especially if you have several trailers —
it’s a bargain.
Meet the Transmitter
The transmitter is powered when you plug in the car
or truck trailer connector. When the lights, brakes, or
flashers are turned on, their power is used to transmit. The
taillights are powered by two D batteries which should last
about 100 hours with the lights on. Most trucks and cars
come prewired with a trailer connector; the standard is a
flat four wire connector with the designations shown
below. Adapters are available for other types.
FOUR WIRE CONNECTOR
1. White wire is ground.
■ FIGURE 1. Transmitter Board.