Chime/Buzzer - Mercedes-Benz 2005 Sprinter Service Manual

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CHIME/BUZZER

DESCRIPTION
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OPERATION
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CHIME/BUZZER
DESCRIPTION
A chime warning system is standard factory-installed
equipment. The chime warning system uses a chime
tone generator and a contactless relay that are soldered
onto the electronic circuit board inside the ElectroMe-
chanical Instrument Cluster (EMIC) to provide audible
indications of various vehicle conditions that may
require the attention of the vehicle operator or occu-
pants. The microprocessor-based EMIC utilizes elec-
tronic messages received from other modules in the
vehicle over the Controller Area Network (CAN) data
bus network along with hard wired inputs to the cluster
to monitor many sensors and switches throughout the
vehicle. In response to those inputs, the circuitry and
internal programming of the EMIC allow it to control
audible outputs that are produced through its on-board
chime tone generator and contactless relay.
The EMIC circuitry and its chime tone generator are
capable of producing the following audible outputs:
• Single Chime Tone - A single, extended "beep-
like" chime tone is issued as a seat belt reminder.
• Fast Rate Repetitive Chime Tone - Repeated
"beep-like" tones that are issued at a fast rate as an
audible alert and to support various visual warnings.
• Slow Rate Repetitive Click Tone - Repeated
"click-like" tones that are issued at a slow rate to
emulate turn signal and hazard flasher operation.
• Fast Rate Repetitive Click Tone - Repeated
"click-like" tones that are issued at a fast rate to emu-
late turn signal flasher operation with a bulb out.
Hard wired circuitry connects the EMIC and the var-
ious chime warning switch and sensor inputs to their
respective modules and to each other through the elec-
trical system of the vehicle. These hard wired circuits
are integral to the vehicle wire harness, which is routed
throughout the vehicle and retained by many different
methods. These circuits may be connected to each other,
to the vehicle electrical system and to the EMIC through
the use of a combination of soldered splices, splice block
connectors, and many different types of wire harness ter-
minal connectors and insulators. Refer to the appropri-
ate wiring information. The wiring information includes
CHIME/BUZZER
TABLE OF CONTENTS
page
DIAGNOSIS AND TESTING - CHIME
WARNING SYSTEM . . . . . . . . . . . . . . . . . . . . . 2
wiring diagrams, proper wire and connector repair pro-
cedures, further details on wire harness routing and
retention, as well as pin-out and location views for the
various wire harness connectors, splices and grounds.
The EMIC chime tone generator and contactless
relay cannot be adjusted or repaired. If the chime
tone generator or contactless relay are damaged or
faulty, the entire EMIC unit must be replaced.
OPERATION
The chime warning system components operate on
battery current received through a non-switched
fused B(+) circuit so that the system may operate
regardless of the ignition switch position. The Elec-
tro-Mechanical Instrument Cluster (EMIC) also mon-
itors the ignition switch position so that some chime
features will only occur with ignition switch in the
On position, while others occur regardless of the igni-
tion switch position.
The chime warning system provides an audible
indication to the vehicle operator or occupants under
the following conditions:
• Engine Oil Level Low Warning - Each time
the ignition switch is turned to the On position, the
EMIC chime tone generator will generate a fast rate
repetitive chime tone if electronic messages are
received over the Controller Area Network (CAN)
data bus from the Engine Control Module (ECM)
indicating that the engine level is too low. The ECM
uses internal programming and hard wired inputs
from the engine oil level and temperature sensor to
determine the engine oil level. This audible warning
occurs in concert with the visual warning provided by
the multi-function indicator in the cluster.
• Fasten Seat Belt Reminder - Each time the
ignition switch is turned to the On position, the
EMIC chime tone generator will generate a single
extended chime tone for a duration of about six sec-
onds, or until the driver side front seat belt is fas-
tened, whichever occurs first. The EMIC uses
internal programming and a hard wired input from
the driver side front seat belt switch to determine
the status of the driver side front seat belt. This
audible warning occurs independent of the visual
warning provided by the EMIC "Seatbelt" indicator.
CHIME/BUZZER 8B - 1
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