TM 9-2320-269-10
USING TRAILER EMERGENCY CONTROL
The following information describes and shows you the location and operation of the emergency trailer (tractor) protection
valve.
1.
Inserted in the air service line leading to the trailer brake system is a tractor protection valve, that is operator
controlled by a cap mounted two-way control valve that provides brake system protection for the towing
vehicle by permitting closure of service and emergency lines leading to the trailer brake hose connections in
the event of a trailer breakaway or other malfunction in the trailer air brake system. The two-way control
valve, which is mounted on the cab instrument panel, may be placed in either of the two positions identified
as NORMAL, (pushed in) and EMERGENCY (pulled out).
2.
When the control valve lever is in the NORMAL position, service and emergency braking functions for the
trailer are normal.
TA 222575
2-79
