What is a ModuLite, ModuLite Lite And ModuLite HD?
A ModuLite is a trailer light power supply module which provides power to the trailer lights
directly from the tow vehicle's battery. By powering the trailer lights in this manner, the
tow vehicle's tail, turn and stop light circuits are not exposed to any additional loads.
Why Is This Important?
In many cases the tail, turn and stop light circuits of today's vehicles are connected with
light gauge wire, designed only to carry enough current to supply the lights the vehicle is
equipped with. Additionally, some vehicles are equipped with sensitive electronic devices,
such as "lamp-out" sensors, which are designed to monitor the vehicle's electrical
system and warn the driver of problems with that system.
The additional load of trailer lights on these devices can cause them to react falsely and
in some cases may lead to their failure.
Which Vehicles Need A ModuLite?
Is the vehicle equipped with any option packages that include a lamp-out sensor or other
electronic devices that could be damaged by attaching trailer lights directly to the vehicle's
electrical system? If so, a ModuLite is required.
Is the trailer being towed equipped with more that one light assembly per side? Does
it have clearance lights, dual tail, turn or stop lights or any other equipment that will
impose an extra load? If so, a ModuLite is required.
Is this the only trailer the driver will ever tow? Consider future requirements as well
as current ones. In future applications, a ModuLite may be required.
Are There Other Ways To Determine The Need For A ModuLite?
Yes. Vehicle manufacturers caution consumers against adding additional loads to electrical circuits.
Consult the vehicle owner's manual when recommending trailer wiring. The following are two examples
from owner's manuals:
Jeep Grand Cherokee
"Do not connect a trailer lighting system directly to the lighting system of your vehicle.
Use an approved trailer wiring harness. Failure to do so could damage the vehicle electrical
system and/or result in personal injury."
Dodge Ram Pickup
"Towing a trailer equipped with more than the standard lighting (turn, tail, stop and back-up
lamps) may cause an abnormally high electrical draw through the headlamp switch, causing the
switch to fail."
Does A ModuLite Take The Place Of A Taillight Convertor?
Yes. ModuLites are designed for use on vehicles that have separate tail, turn and stop light circuits
and converts them to standard trailer light wiring configuration. ModuLite and ModuLite HD also
feature a hazard flasher override circuit. If the hazard flashers are engaged and brakes are
applied, brake lights will be shown on the trailer. This is an added safety feature that most
taillight convertors do not provide.
Can I Still Use A ModuLite If I Don't Need A Convertor?
Yes. They can be used on any vehicle that requires a reduction of load on its electrical system.
What Other Features Do ModuLites Provide?
Because a ModuLite receives its power directly from the tow vehicle's battery and not the turn signal
circuit, the need for a heavy duty turn signal flasher is eliminated. Their advanced circuitry provides
maximum trailer light brightness.
How Long Does It Take To Install A ModuLite?
Approximately 30 to 45 minutes depending on the difficulty of running the power supply wire from the
battery to the rear of the vehicle.
What Does The Wiring Kit (18151) Contain?
Wiring kit 18151 comes with everything needed to install a ModuLite including 20 ft. of special undercar
12 ga. wire, fuse, fuse holder and attaching terminals.
Which ModuLite Do I Need?
To determine which trailer light power module you may need, follow these basic guidelines. Add the number
of amps required on the trailer you will be towing (see below). If the total is less than 4 amps
per light circuit, ModuLite-Lite is recommended. If the total is between 4 and 10 amps ModuLite is recommended.
If the total is more than 10 amps, a ModuLite HD is required. Remember to also consider your future
towing needs. While ModuLite-Lite may be adequate for their current trailer, a different trailer may have a
higher amperage requirement making ModuLite or ModuLite HD the better choice.
Estimating Trailer Amperage Per Circuit