Roadmaster Towed-Vehicle Wiring: Diode & Smart Diode Kit Guide

When flat towing a vehicle behind a motorhome, the towed vehicle's rear lights need to show the motorhome's turn, brake and running-light signals. Roadmaster offers several ways to do this, and selecting by the part number alone can lead to the wrong kit. Start with the towed vehicle's bulb type and lighting electronics, then choose the connecting cord and installation method.

Which Roadmaster wiring arrangement fits the job?

Standard diode kits

Roadmaster 152, 154 and 15267 use four Hy-Power diodes to integrate with existing taillights. These versions are not the choice for a vehicle that needs Smart Diodes for multiplex or variable-voltage lighting.

Smart Diode kits

Choose 153782 for compatible incandescent systems or 153789 for LED systems. Certain Jeep LED/ParkSense configurations need the specialized 152789 kit.

Independent bulbs

Roadmaster 155 installs separate bulbs inside compatible taillight housings instead of splicing into factory lamp wiring. Housing size and bulb clearance must be checked first.

Why Smart Diodes matter: Some modern vehicles send brake and running-light signals through the same circuit at different voltages. A conventional diode can give an incorrect lighting result in those applications. LED versus incandescent is a separate selection question—two vehicles with multiplex lighting may still need different Smart Diode kits.

Roadmaster towed-car wiring kits by MPN

MPN Wiring method What makes it different
152 Economy diode kit Standard lighting; connecting cord separate
154 Universal diode kit Standard lighting; four-flat cord included
15267 All-in-one diode kit Standard lighting; seven-to-six cord and socket
153782 Incandescent Smart Diode Variable-voltage / multiplex lighting; incandescent
153789 LED Smart Diode Variable-voltage / multiplex lighting; LED
152789 Jeep LED / ParkSense Smart Diode Specialized Jeep electronics
155 Separate bulb-and-socket kit Avoids splicing factory taillight wires

The 152 and 154 use the same conventional four-diode approach, but the 152 economy package does not include the six-foot motorhome-to-towed-car cord supplied with 154. The 15267 combines conventional diodes with a seven-to-six-wire coiled cord, socket and bracket. If multiplex lighting is present, check Smart Diode alternatives instead.

Find the matching Roadmaster products

These product cards open the individual NewRVParts listings for the exact part numbers. Availability, current price and any product-specific package details appear on each listing.

Roadmaster 152 economy four-diode flat-towing wiring kit, NewRVParts product image

Roadmaster 152

Economy diode kit

Four Hy-Power diodes and a 27-foot four-wire harness. The RV-to-car power cord is sold separately.

View this Roadmaster wiring kit
Roadmaster 154 four-diode taillight wiring kit with six-foot four-flat cord

Roadmaster 154

Universal diode kit

Four Hy-Power diodes, a 27-foot harness and a six-foot four-flat power cord connecting the vehicles.

View this Roadmaster wiring kit
Roadmaster 15267 all-in-one towed vehicle wiring kit with seven-to-six cord

Roadmaster 15267

All-in-one diode kit

Four Hy-Power diodes, vehicle harness, coiled seven-to-six-wire cord, front socket and mounting bracket. Not for multiplex or variable-voltage lighting.

View this Roadmaster wiring kit
Roadmaster 153782 Smart Diode wiring kit for towed vehicles with incandescent taillights

Roadmaster 153782

Incandescent Smart Diode

Two Smart Diodes designed for compatible vehicles with incandescent taillight bulbs. Connecting cord selected separately.

View this Roadmaster wiring kit
Roadmaster 153789 Smart Diode wiring kit for LED taillight systems

Roadmaster 153789

LED Smart Diode

Two Smart Diodes for compatible LED-taillight applications. Not the same version as the incandescent kit; connecting cord is separate.

View this Roadmaster wiring kit
Roadmaster 152789 Jeep ParkSense and LED taillight Smart Diode wiring kit

Roadmaster 152789

Jeep LED / ParkSense Smart Diode

Smart Diode kit for specified Jeep LED-taillight and ParkSense applications. Confirm exact model, year and equipment in Roadmaster FitMaster.

View this Roadmaster wiring kit
Roadmaster 155 bulb and socket flat towing tail light wiring kit

Roadmaster 155

Separate bulb-and-socket kit

Two 1157 bulbs and sockets, a 30-foot harness and six-foot four-flat connecting cord. Requires suitable lamp-housing room and a one-inch socket hole.

View this Roadmaster wiring kit

Check the vehicle before choosing a kit

  1. Confirm the vehicle is approved for flat towing. Follow the vehicle manufacturer's recreational towing procedures and transmission requirements independently of the wiring choice.
  2. Identify LED or incandescent rear lamps. Do not identify bulb technology by the colour of the outside lens.
  3. Check for multiplex / variable-voltage signalling. Roadmaster FitMaster is the appropriate starting point for determining whether standard or Smart Diodes are specified for a particular year, make, model and lighting arrangement.
  4. Check Jeep ParkSense equipment. The presence of certain proximity-sensor systems can change the required wiring approach. Part 152789 is not a blanket fit for every Jeep.
  5. Confirm both ends of the towing cord. A four-flat kit, a seven-to-six connection and a kit without a cord represent different installations. Do not assume the towing connection is included just because the taillight wiring is.
  6. Check extra-bulb clearance for part 155. Its socket needs a one-inch mounting hole; the bulb projects 1-7/8 inches from the hole and must remain at least 1/4 inch away from the lens. Not all lamp housings have enough space.
Does Roadmaster 152 include the cord between motorhome and car?

No. Roadmaster 152 includes the towed-car wiring harness and four Hy-Power diodes. A compatible connecting power cord is needed separately. The 154 kit includes a six-foot four-flat connecting cord.

Are 153782 and 153789 interchangeable?

They serve different lamp types. Both use Smart Diodes, but 153782 is the incandescent-bulb kit and 153789 is the LED-bulb kit. Match the vehicle lighting configuration before choosing.

Does the all-in-one 15267 work on multiplex taillights?

No. Roadmaster specifies the 15267 four-Hy-Power-diode kit for non-variable-voltage applications. For multiplex lighting, use the appropriate Smart Diode design confirmed by Roadmaster for the vehicle.

Is a towed-vehicle charge line included in the taillight kits?

Do not assume so. Battery maintenance while towing is a separate electrical function from taillight signalling. Depending on the vehicle and motorhome, a charge line may be required in addition to the lighting kit.

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