Bendix Commercial Vehicle Systems MC-12 MODULATOR CONTROLLER ASSY - Manual (Page 6)

6
SERVICE CHECKS
Ensure that all wiring and connectors are secure and free
from visible damage. Although the MC-12
™ modulator
assembly contains self check diagnostics, the LED (Light
Emitting Diode) display should be inspected to ensure that
the LEDs are functional. With the trailer brakes actuated, a
magnet (800 gauss; capable of picking up 3 ounces) held to
the LED reset area should cause all of the LEDs to illuminate.
If one or more of the LEDs DO NOT ILLUMINATE and the
optional status light indicates proper system function, the
non illuminated LED(s) should be noted for future reference.
Although the diagnostic capabilities will be limited, the
system will continue to function as designed.
The MC-12 ™ modulator assembly monitors the electronics
of the system upon initial trailer brake application. However,
the vehicle should be road tested periodically to verify proper
solenoid function. The solenoids can be tested by making
an aggressive trailer stop from a speed of 20 m.p.h. When
an antilock stop is made, solenoid pulsation creates an
audible burst of air, which can be heard from the outside of
the trailer.
WARNING! PLEASE READ AND FOLLOW
THESE INSTRUCTIONS TO
AVOID
PERSONAL INJURY OR DEATH:
When working on or around a vehicle, the following
general precautions should be observed at all
times.
1. Park the vehicle on a level surface, apply the
parking brakes, and always block the wheels.
Always wear safety glasses.
2. Stop the engine and remove ignition key when
working under or around the vehicle. When
working in the engine compartment, the engine
should be shut off and the ignition key should be
removed. Where circumstances require that the
engine be in operation, EXTREME CAUTION should
be used to prevent personal injury resulting from
contact with moving, rotating, leaking, heated or
electrically charged components.
3. Do not attempt to install, remove, disassemble or
assemble a component until you have read and
thoroughly understand the recommended
procedures. Use only the proper tools and observe
all precautions pertaining to use of those tools.
4. If the work is being performed on the vehicle’s air
brake system, or any auxiliary pressurized air
systems, make certain to drain the air pressure from
all reservoirs before beginning ANY work on the
vehicle. If the vehicle is equipped with an AD-IS
™
air dryer system or a dryer reservoir module, be
sure to drain the purge reservoir.
5. Following the vehicle manufacturer’s
recommended procedures, deactivate the electrical
system in a manner that safely removes all
electrical power from the vehicle.
6. Never exceed manufacturer’s recommended
pressures.
7. Never connect or disconnect a hose or line
containing pressure; it may whip. Never remove a
component or plug unless you are certain all
system pressure has been depleted.
8. Use only genuine Bendix ® replacement parts,
components and kits. Replacement hardware,
tubing, hose, fittings, etc. must be of equivalent
size, type and strength as original equipment and
be designed specifically for such applications and
systems.
9. Components with stripped threads or damaged
parts should be replaced rather than repaired. Do
not attempt repairs requiring machining or welding
unless specifically stated and approved by the
vehicle and component manufacturer.
10. Prior to returning the vehicle to service, make
certain all components and systems are restored to
their proper operating condition.
FIGURE 8 - ELECTRICAL CONNECTOR
A
B
C
D
E
F
G
H
J
K
L
M
N
P
SENSOR 1
SNS 1
SENSOR 2
SNS 2
SENSOR 1
SNS 1
SENSOR 2
SNS 2
OPTIONAL
TRACTOR
MOUNTED
STATUS
LIGHT
OPTIONAL
CONSTANT
POWER
(TRACTOR
IGNITION)
GROUND
STOPLIGHT
SWITCH
POWER
OPTIONAL
TRAILER
MOUNTED
STATUS
LIGHT