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2 wIRe SySTeMS (2w)
2-wire systems can be identified by the use
of a single bulb on each side of the vehicle/
trailer to provide both stop lamp and turn
signal illumination.
3 wIRe SySTeMS (3w)
3-wire systems utilize separate wires
to provide power to the stop lamp and
turn signal bulbs. 3-wire systems can be
identified by twin bulbs in each side of the
vehicle/trailer.
PULSe wIDTH MODULATION SySTeMS (PwM)
These are systems that vary the signal intensity over one wire to initate more than one lighting
function. One wire can control more than one light function. PWM systems can be either
incandescent or LED. There are two types of PWM systems ST and STT.
ST SySTeMS
Have two wires, one wire that contains both
stop and tail functions, and a separate wire
on each side that contains the turn signal
functions.
STT SySTeMS
Have one wire that contains stop, tail and
turn functions.
Note: Refer to page 4-11 for ST & STT system vehicle applications
Vehicle Side
Trailer Side
Connector
Converter
STOP
TURN
TAIL
TAIL
STOP
TURN
Vehicle Side Trailer Side
Connector
STOP
TURN
TAIL
STOP
TURN
TAIL
Vehicle Side
Trailer Side
Connector
PMw Converter
STOP
TURN
TAIL
TAIL
STOP
TURN
Vehicle Side
Trailer Side
Connector
PMw Converter
STOP
TURN
TAIL
STOP
TURN
TAIL
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