"Nothing stays the same except change itself" - Anonymous


The purpose of this document is to give everyone the same story at the same time. This is an attempt to answer as many questions as possible about TMC's new trailer so we can make the transition quickly, painlessly, and safely.

TMC's new trailer has disc brakes, and not drum brakes such as those on TMC's original trailer and Red's current trailer. The new disc brakes require an additional electrical connection to the tow vehicle reverse lights to lock out the brakes when backing up the trailer.


  • Here is what the club will be doing to cut over to the new system:

    1. The Club will be converting all three trailer electrical connectors to FLAT-FIVE connectors by Thursday, September 18th. No more round-four connectors!

    2. We will provide car-end FLAT-FIVE connectors to each Launcher (or equivalent value toward an adaptor for your present setup) and encourage you to convert your tow vehicle to a FLAT-FIVE system, detailed below.

    3. We will build FLAT-FIVE to ROUND-FOUR CONVERTERS for each trailer, which will be stored in the shed by the clipboards. These converters will be provided as a temporary solution for towing RED and THE DYNE ONLY, with the understanding that everyone cannot upgrade immediately.

    4. We will provide technical support for each launcher, as needed.

  • Here is what we ask you to do:

    1. Upgrade your tow vehicle to a FLAT-FIVE trailer connector. There are several options, some of which are outlined below. It's not that big a deal, as you'll see. We'll supply the connector you need and we'll provide converters to get you through the transition period.

    2. Understand that towing TMC on the new trailer without an electrical brake lockout hooked up to your reverse lights is both dangerous and illegal. Doing so is virtually the same as running without safety chains or other required equipment. Please upgrade as soon as possible!

    3. Adjust your retrieval routine for TMC to completely and thoroughly rinse the brake assemblies with a direct spray of water. There is no brake flush system on the new trailer.


While we understand that not everyone can just drop everything and upgrade their tow vehicle's electrical connectors, we also need to make this transition quickly, seamlessly, and SAFELY. We recognize that each individual's situation is different, and we're prepared to help out to the greatest extent possible. If you have questions or require assistance, please call any club Officer or Boat Manager.


You'll notice two major differences with the disc brakes on TMC's new trailer:

(1) The disc brakes will engage MOST of the time you attempt to back up, even on a level surface. If you're not equipped with the right electrical connection (explained below), you could find yourself in dangerous situation should you need to back up in traffic.

(2) There is no flushing system because the brakes are exposed and can be rinsed with a direct spray from a hose. This is a time-saver. Disc brakes are also easier to inspect and maintain.

Otherwise, the disc brakes on the new trailer are just like the drum brake systems we've been using. As the tow vehicle stops, the force of the trailer pushing forward into the hitch compresses the actuator mechanism, and this engages the brakes. Everything is the same until you go to back up the trailer.

Keep in mind that disc brakes have become the standard on most boat trailers. Not only does this change bring the club up to date with the industry, it is inevitable that future club trailers will also have disc brakes.

Table I summarizes both brake systems.

ACTUATOR SYSTEM Hydraulic Surge System, tongue-mounted Hydraulic Surge System, tongue-mounted
REVERSE LOCKOUT REQUIRED Required only when backing up an incline ALWAYS required
REVERSE LOCKOUT MECHANISM Mechanical Lockout - lever mounted on tongue Electrical Lockout* - engaged by tow vehicle reverse lights
FRESH WATER RINSING Flush Kit Exposed, spray thoroughly with hose
EMERGENCY BREAKAWAY SWITCH Mechanical, engaged via cable/lanyard hooked to tow vehicle Mechanical, engaged via cable/lanyard hooked to tow vehicle
* Not to be confused with "electric trailer brakes", where the brakes themselves are electrically engaged.


A FLAT-FIVE trailer connector is so named because it carries five signals, shown in Table II, below. They look like and interconnect with the FLAT-FOUR connectors commonly used on boat trailers.

Please note that FLAT-FOUR connectors don't carry the REVERSE LIGHTS signal needed to lock out the disc brakes when backing up. We therefore strongly discourage the use of FLAT-FOUR connectors with club trailers.

White * Ground Vehicle Frame
Brown * Running (Parking) Lights Vehicle Running Lights
Yellow * Left Turn Signal & Brake Light Left Turn/Brake
Green * Right Turn Signal & Brake Light Right Turn/Brake
Blue Trailer Brake Lockout & Trailer Reverse Lights(!) Vehicle Reverse Lights
* Denotes the same signal and wire color as our present ROUND-FOUR system.


For most Launchers, upgrading will entail running an extra lead from the reverse lights of their tow vehicle and connecting this and the existing four wires to a FLAT-FIVE connector. Many of us have a reverse lights wire already in place in a factory-installed harness at the rear of the vehicle.

If you need it, the club will provide you with a FLAT-FIVE car-end connector that comes with a foot or two of wiring. This connector will work with all three club trailers, although TMC's is the only trailer that will use all five connections.

Note that FLAT-FOUR connectors should NOT be used with club trailers!
  • You have a ROUND-FOUR on your vehicle and tow ONLY club trailers
    This is the setup most of us use. Simply replace your ROUND-FOUR connector with the FLAT-FIVE provided by the club and connect the blue lead to your reverse lights.

  • You have a ROUND-FOUR on your vehicle and tow other trailers
    In the case, you likely use a converter to go from your ROUND-FOUR to whatever other trailers you tow. Simply replace your Round-four connector with the FLAT-FIVE provided by the club and connect the blue lead to your reverse lights.

  • You have a FLAT-FOUR installed and use a converter to go from it to ROUND-FOUR only when you tow club trailers.
    Install a new FLAT-FIVE and either build a simple converter to go from it to FLAT-FOUR or just plug whatever FLAT-FOUR you use into your new FLAT-FIVE. Alternately, you can keep your FLAT-FOUR and install the new FLAT-FIVE in parallel to it.

  • You have a FACTORY or AFTERMARKET connector and covert from it to ROUND-FOUR to tow club trailers
    You may be one of the lucky ones. If you have a ROUND-7 connector, chances are good you already have reverse lights at your connector and only need to build or purchase a converter to go to FLAT-FIVE. Call Dewey or Trudgen if you think you have this setup, as they know what to do. Newer vehicles, especially trucks and SUVs, have bundles of wires tucked under the rear end which carry most of the signals required for towing all types of trailers, including reverse lights. A quick call to your dealer or local trailer shop might help in locating the reverse lights wire.