Volvo VNL Service Manual page 39

Group 30 Electrical System—VNL, VNM
Stop/Hazard/Turn Lights
Hazard and Turn Logic Diagram
The tail lamps use a single bulb for the stop, hazard and
turn indicators. For this reason, the rear hazard and tail
lamps function differently than the tractor front and trailer
rear signals. Application of the brakes overrides the tractor
rear hazards, and turn signals override the tractor brake
lights and rear hazards.
Hazard/Turn Lights
•
The hazard and turn indicators are powered through a
Battery Maxi-fuse through wire 110, which powers the
flasher unit. Wire 121 feeds power from the flasher
unit to the hazard switch.
•
When the hazard switch is OFF , wire 111 powers the
turn signal switch.
•
When the left turn signal is ON , power comes through
the switch to wires 112 and 115.
•
When the right turn signal is ON , power comes
through the switch to wires 113 and 116.
•
When the hazard switch is ON (fed by wire 121), wire
122A powers the switch illumination, and power is
sent to wires 112 and 113 for the tractor front and
trailer turn lights. The hazard switch ground is 0J-B.
Design and Function
W3001003
37