b. Tractor Trucks
Electrical cable and connector is
connected to the semitrailer
electrical receptacle to provide
electrical power to the semitrailer.
Emergency airbrake hose line and
c o u p l i n g is connected to the
emergency airbrake coupling on the
trailer. The semitrailer emergency
brake system is activated when the
"regular" air system fails.
Service airbrake hose line and
coupling is connected to the service
airbrake receptacle on the trailer to
provide air to the semitrailer service
Airbrake hose coupling shutoff
cocks are turned on to allow air to
enter the semitrailer brake system,
must be turned off otherwise,
except when checking or servicing.
Locking plunger lever is pulled forward to unlock fifth wheel coupling jaws and release
semitrailer from tractor or allow tractor to be coupled with semitrailer.
Locking plunger safety latch is swung to one side to use locking plunger lever.
Fifth wheel wedges are moved toward the tractor rear for highway travel, toward the
front for cross-country operations.