
reaching operating temperature. The heater's con-
trol unit controls and monitors combustion opera-
tion through various inputs and outputs that are
contained inside the heater assembly. The supple-
mental heater connects to the vehicle's heater hoses
and uses a separate fuel supply line and fuel pump
that connects to the vehicle's fuel tank. Unlike the
Heater Booster, the Cabin Heater Assembly has an
integral coolant pump which allows heater opera-
tion without the vehicle's engine running. In addi-
tion, a programmable timer module can also be
added to this system. Neither the Cabin Heater
Assembly nor the Heater Booster Assembly are
connected to the CAN Bus. Communication be-
tween the heater's control unit and the DRBIIIt
occurs through the Diagnostic Link Connector
(DLC) via a K-Line.
3.3.2.2 VENTING THE HEATER'S EXHAUST
WARNING: NEVER OPERATE THE HEATER
IN AN ENCLOSED AREA THAT DOES NOT
HAVE EXHAUST VENTILATION FACILITIES.
ALWAYS VENT THE HEATER'S EXHAUST
WHEN OPERATING THE HEATER. FAILURE
TO FOLLOW THESE INSTRUCTIONS CAN
RESULT IN PERSONAL INJURY OR DEATH.
WARNING:
ALLOW THE HEATER ASSEMBLY TO
COOL BEFORE PERFORMING A COMPONENT
INSPECTION/REPAIR/REPLACEMENT. FAILURE
TO FOLLOW THESE INSTRUCTIONS CAN
RESULT IN PERSONAL INJURY OR DEATH.
CAUTION: When using a powered exhaust
ventilation system, do not attach the exhaust
ventilation hose directly to the heater's
exhaust pipe. Too much suction can prevent
heater operation.
When using a powered exhaust ventilation sys-
tem, affix the ventilation hose to the heater's ex-
haust pipe or to the vehicle in such a manor that the
end of the ventilation hose remains approximately
three inches away from the end of the heater's
exhaust pipe.
When using a non-powered exhaust ventilation
system, affix the ventilation hose directly to the
heater's exhaust pipe.
3.3.2.3 SYSTEM DIAGNOSTICS
CAUTION: Always Perform The Heater
Pre-Test (In The Diagnostic Procedures) Prior
To Performing Any Other Test For The Test
Result To Be Valid.
Fault detection is through stored Diagnostic
Trouble Codes (DTCs). DTCs are displayed by the
DRBIIIt. The heater's control unit will store up to
five DTCs in its memory. If the control unit detects
a new fault in the system, one that is not already
stored in its memory, it will clear the oldest of the
five stored DTCs, and it will store the new fault's
DTC. If the control unit detects a reoccurrence of a
stored fault, it will overwrite that fault's DTC with
the most recent occurrence.
DIAGNOSTIC TIPS
SENSOR VALUES
Operating Voltage
The normal range for the Operating Voltage is from
10 volts to 15 volts. The value indicates the voltage
at the heater 's Fused B+ terminal.
Heating Capacity
The normal range for the heating capacity is from
0% to 100%. The value indicates the momentary
output of the auxiliary heater in % of the maximum
output.
Coolant Temperature
The value indicates the current coolant tempera-
ture.
Flame Sensor Resistance
The normal range for the Flame Sensor is from 750
ohms to 2270 ohms. The value indicates the mo-
mentary resistance of the Flame Sensor.
INPUT/OUTPUT STATUS
Dosing Pump
A status of9ON9indicates that the Dosing Pump is
operational. A status of9OFF9indicates the Dosing
Pump is not operational.
Glow Pin
A status of9ON9indicates that the Glow Pin is
energized. A status of9OFF9indicates the Glow Pin
is not energized.
Combustion Fan
A status of9ON9indicates that the Combustion Fan
is operational. A status of9OFF9indicates the
Combustion Fan is not operational.
Circulation Pump
A status of9ON9indicates that the Circulation
Pump is operational. A status of9OFF9indicates the
Circulation Pump is not operational.
Front End Blower
A status of9ON9indicates that the Blower Motor is
operational. A status of9OFF9indicates the Blower
Motor is not operational.
8
GENERAL INFORMATION

Do not blend other specific fuel additives with die-
sel fuel. They only result in unnecessary cost, and
may be harmful to the engine operation.
POWER STEERING FLUID
No fluid service required. Filled with Power Steer-
ing Fluid approved to MB 236.3, such as Mobil
ATF-D (Exxon Mobil Corporation) or equivalent.
OPERATION - AUTOMATIC TRANSMISSION
FLUID
The automatic transmission fluid is selected based
upon several qualities. The fluid must provide a high
level of protection for the internal components by
providing a lubricating film between adjacent metal
components. The fluid must also be thermally stable
so that it can maintain a consistent viscosity through
a large temperature range. If the viscosity stays con-
stant through the temperature range of operation,
transmission operation and shift feel will remain con-
sistent. Transmission fluid must also be a good con-
ductor of heat. The fluid must absorb heat from the
internal transmission components and transfer that
heat to the transmission case.
FLUID CAPACITIES
SPECIFICATIONS - FLUID CAPACITIES
DESCRIPTION SPECIFICATION
ENGINE COOLANT
10 Liters 10.5 Quarts
ENGINE OIL
9.0L without Filter Re-
placement9.5 Quarts with Filter
Replacement
AUTOMATIC TRANSMISSION
Service Fill - NAG1 5.0 L (10.6 pts.)
O-haul Fill - NAG1 7.7 L (16.3 pts.)
Dry fill capacity Depending on type and size of inter-
nal cooler, length and inside diameter of cooler lines,
or use of an auxiliary cooler, these figures may vary.
(Refer to appropriate 21 - TRANSMISSION/AUTO-
MATIC/FLUID - STANDARD PROCEDURE).
REAR AXLE .03L (1 oz.)
8 1/2 1.8 L (4.0 pts.)
FUEL TANK
Primary 100 L (26.4 gal.)*
Reserve 10.5 L (2.8 gal.)*
*Nominal refill capacities are shown. A variation may
be observed from vehicle to vehicle due to manufac-
turing tolerance and refill procedure
DESCRIPTION SPECIFICATION
POWER STEERING SYSTEM
Power steering fluid capacities are dependent on
engine/chassis options as well as steering gear/cool-
er options. Depending on type and size of internal
cooler, length and inside diameter of cooler lines, or
use of an auxiliary cooler, these capacities may vary.
Refer to 19, Steering for proper fill and bleed proce-
dures.
FLUID FILL / CHECK LOCA-
TIONS
INSPECTION - FLUID FILL / CHECK LOCA-
TIONS
The fluid fill/check locations and lubrication points
are located in each applicable group.
HOISTING
STANDARD PROCEDURE - HOISTING
Refer to the Owner's Manual for emergency vehicle
lifting procedures.
WARNING: THE HOISTING AND JACK LIFTING
POINTS PROVIDED ARE FOR A COMPLETE VEHI-
CLE. WHEN A CHASSIS OR DRIVETRAIN COMPO-
NENT IS REMOVED FROM A VEHICLE, THE
CENTER OF GRAVITY IS ALTERED MAKING SOME
HOISTING CONDITIONS UNSTABLE. PROPERLY
SUPPORT OR SECURE VEHICLE TO HOISTING
DEVICE WHEN THESE CONDITIONS EXIST.
FLOOR JACK
When properly positioned, a floor jack can be used
to lift a vehicle. Support the vehicle in the raised
position with jack stands at the front and rear ends
of the frame rails.
CAUTION: Do not lift vehicle with a floor jack posi-
tioned under:
²An axle tube.
²A body side sill.
²A steering linkage component.
²A drive shaft.
²The engine or transmission oil pan.
²The fuel tank.
²A front suspension arm.
VALUBRICATION & MAINTENANCE 0 - 5