Horn Controls; Dash-Mounted Brake Controls - freightliner M2 Plus 2023 Manual

05/09/2022
Fig. 4.9, Pretrip Light Test Switch
spotlamp assembly mounted above the driver's door,
or one above each door.
Utility Lamps
Utility lamps can be swivel-mounted on the upper
half of the cab, mounted on the exhaust support, or
flush-mounted on the back of the cab or sleeper.
Press the upper half of the switch to turn the utility
lamps on or off.
When activated, a red indicator light in the switch is
illuminated.
Backup Lamps
Backup lamps activate only when the vehicle is in
reverse, and are designed to be used while backing
up at night.

Horn Controls

Air Horn
Air horn(s) may be mounted on the roof of day cabs,
or under the driver-side floor for sleeper cabs. The
air horn is controlled by a wire lanyard that hangs
down inboard by the driver's door. See
Pull downward on the lanyard to sound the air horn.
Electric Horn
The electric horn is activated by pressing down on
the top of the steering wheel center pad.
The horn will sound for the duration that the button is
pressed, up to 60 seconds. The electric horn will
operate regardless of the position of the ignition key.

Dash-Mounted Brake Controls

NOTE: See Chapter 11
additional information about brake systems.
LIGHT
TEST
f611436
Fig. 4.10.
Brake Systems, for
11/ 29 /20 22
1. Lanyard
Fig. 4.10, Air Horn Control
Parking Brake Control Valve
The yellow diamond-shaped knob operates the
parking brake valve. See
to apply both the tractor and the trailer spring parking
brakes. Push both the parking brake and the trailer
air supply knobs in to release the tractor and trailer
spring parking brakes. Before the spring parking
brakes can be released, the air pressure in either air
brake system must be at least 65 psi (447 kPa).
If the trailer is not equipped with spring parking
brakes, pull the parking brake valve out to apply the
tractor parking brakes and the trailer service brakes.
Trailer Air Supply Valve
The red octagonal-shaped knob operates the trailer
air supply valve, which charges the trailer air supply
system and releases the trailer spring parking
brakes. See Fig. 4.7.
After the vehicle and its air hoses are connected to a
trailer and the pressure 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
Driver Controls
1
f612196
Fig. 4.7. Pull the knob out
4.6