30
Installation
5.2.4.2 Air Line Installation
1. Ensure that all unused air ports are plugged and that the exhaust port is facing DOWN.
2. Look at the air line installation to verify that all air lines are correctly installed.
If the ECU/dual modulator valve assembly is mounted with the control port facing the FRONT of
the trailer, the air lines for the three delivery ports labeled 2.1 must be routed to CURBSIDE; the
air lines for the three delivery ports labeled 2.2 on the opposite side of the valve must be routed to
ROADSIDE. Figure 27.
If the ECU/dual modulator valve assembly is mounted with the control port facing the REAR of the
trailer, the air lines for the three delivery ports labeled 2.1 must be routed to ROADSIDE; the air
lines for the three delivery ports labeled 2.2 on the opposite side of the valve must be routed to
CURBSIDE. Figure 28.
Fig. 27
4014007a
CONTROL
PORT
DELIVERY PORTS 2.2
DELIVERY
PORTS 2.1
Fig. 28
4014011a
CONTROL
PORT
DELIVERY
PORTS 2.2
DELIVERY PORTS 2.1
3.
3.
For 4S/3M installations:
For 4S/3M installations:
Repeat this test for the external modulator valve. The external relay valve is
an axle control valve. It controls the brake chambers on one or two axles. It is important that delivery
lines from Port 2 are plumbed as shown in Figure 16, Figure 17 and Figure 18. The 4S/3M system is
designed to be used with a variety of trailer con
fi
gurations.
4. If the air lines are not correctly routed, perform the necessary repairs.
5.2.4.3 Perform End of Line Test
1. Apply 12 volts DC power to the ABS.
2. Listen for the ECU/dual modulator valve assembly to click four times (six times for a 4S/3M).
