To activate the high range, press the lower half of the
switch. Press the upper half to return to N-TRL.
To activate the low range, press the upper half of the
switch. Press the lower half of the switch to return to
N-TRL, and then press the lower half again to switch
to the high range.
Brake Controls
Parking Brake Control Valve
NOTE: See Chapter 12 for detailed information
about brake systems.
NOTICE
Do not step on the service brake pedal while the
parking brakes are applied. To do so can cause
damage to the brake mechanisms.
The yellow diamond-shaped knob operates the park-
ing brake valve. Pulling the knob out applies both the
tractor and trailer spring parking brakes. See
Fig. 5.30. Pushing the knob in releases the tractor
spring parking brakes.
If the trailer is not equipped with spring parking
brakes, pulling out the parking brake valve applies
the tractor parking brakes and the trailer service
brakes.
Trailer Air Supply Valve
The red octagonal-shaped knob operates the trailer
air supply valve. See Fig. 5.30. After the vehicle and
its air hoses are connected to a trailer and the pres-
sure in the air system is at least 65 psi (447 kPa),
push the trailer air supply valve knob in (and leave it
in) to charge the trailer air supply system and release
the trailer spring parking brakes.
Pull the trailer air supply valve out before disconnect-
ing a trailer or when operating a vehicle without a
trailer.
Trailer Brake Lever
The trailer brake lever is used for applying the trailer
service brakes without applying the truck or tractor
service brakes. It is usually mounted on the right-
hand control panel. See
Fig. 5.31. The valve can be
partially or fully applied, but in any partially on posi-
tion it will be overridden by a full application of the
service brake pedal. Moving the lever down applies
the trailer brakes, while moving it up releases the
trailer brakes. The lever will automatically return to
the up position when it is released.
Antilock Braking System
The Meritor
™
WABCO® Antilock Braking System
(ABS) passively monitors vehicle wheel speed at all
times, and controls wheel speed during emergency
stops or wheel lock situations.
During emergency or reduced-traction stops, fully
depress the brake pedal until the vehicle comes to a
safe stop. Do not pump the brake pedal. With the
brake pedal fully depressed, the ABS will control all
wheels to provide steering control and a reduced
braking distance.
The ABS is designed to communicate with a trailer
ABS, if they are compatible. Compatibility will result
in the illumination of the TRAILER ABS lamp during
vehicle start-up and fault detection. The TRAILER
f610291
1
2
03/10/99
1. Trailer Air Supply Valve (red knob)
2. Parking Brake Control Valve (yellow knob)
Fig. 5.30, Brake Valve Control Knobs
10/17/2001
f610591
Fig. 5.31, Trailer Brake Lever
Driver Controls
5.12
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