Note: this wiring method can only be used if the brake
lights illuminate with the engine off and the towed vehicle
has separate lighting. See page 4.
Note: if the motorhome has combined brake and turn
signals, use Figure 7 to wire the towed vehicle. If the
motorhome has separate brake and turn signals, visit
roadmasterinc.com. Use the ‘Separate towed vehicle to
separate’ motorhome wiring diagram under ‘Support.'
Note: if a 3-to-2 converter has been installed in a mo-
torhome with separate brake and turn signals, wire the
towed vehicle according to Figure 7.
To test for a 3-to-2 converter, use a test light to find the
turn signal and brake light circuits on the motorhome elec-
trical socket. If the same circuit energizes both the turn
signals and the brake lights, a 3-to-2 converter has been
installed. If the turn signal and brake lights have separate
circuits, a 3-to-2 converter has not been installed.
1.
Cut the factory turn signal, taillight and brake light
wires, as close to the lights as possible.
2.
Install the six diodes in line, as shown in Figure 7.
Install the diodes as close to the lights as possible.
CAUTION
Attach the diodes as close to the vehicle’s lights as
possible, to avoid interaction with other circuits which
may be tied into the center brake light, the running
lights, the turn signals or the brake light wires.
Figure 7
Attaching the diodes farther away may cause the
towed vehicle’s lights to work improperly and may
also cause damage to other electrical components
in the vehicle.
3.
On each side, jump the brake and turn signal diodes,
as shown in Figure 7.
CAUTION
Unless the brake and turn signal diodes are jumped,
the towed vehicle’s brake light circuits will override
the motorhome’s turn signals — the towed vehicle’s
turn signals will not operate in conjunction with the
motorhome’s turn signals, as required by law.
4.
Test the installation…
A. If the motorhome has a combined lighting system
(Figure 2)…
1. The towed vehicle’s turn signals and brake lights
will both flash (each side) when the motorhome’s turn
signal is on; and
2. When the motorhome’s turn signal and brake signal
are both on (each side), the towed vehicle’s brake lights
will stay illuminated, while the turn signal flashes.
B. If the motorhome has a separate lighting system
(Figure 2), the towed vehicle’s turn signals and brake lights
will illuminate identically to the motorhome’s.
Install six diodes
7
