MCi Crusader II 1989 Maintenance Manual page 122

Date 1-1-89.
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MC-9 MAINTENANCE MANUAL
Procedure #4
If the fuse was not burned out after Procedure #2 step 6,
and the refrigerator is not cooling after 1 to 2 hours of operation,
proceed with the following:
1. Turn the main battery switch "OFF."
2. Remove the refrigerator from the cabinet; refer to
REMOVAL OF REFRIGERATOR.
3. Disconnect the yellow and black feed wires from the
refrigerator heater element lead wires.
4. Using an ohmmeter set on the R x 1 scale, check the yel-
low and black leads of the heater element A reading of 3.6 ohms
(.:!:..2 ohms) indicates that the heater element is functioning
correctly. If no resistance or very high resistance is found,
replace the refrigerator heater element
5. If the heater element is functioning correctly, place one
ohmmeter probe on the black feed wire that was disconnected
from the heater element Place the other probe on the white
(negative) 24V feed wire that was disconnected from stud #10
of the ten terminal stud block. If there is infinite resistanc_e.
adjust the thermostat control to either extreme while observing
the ohmmeter scale. If the ohmmeter registers any resistance
while adjusting the thermostat. the circuit is functioning
correctly. If the ohmmeter registers no resistance while
adjusting the thermostat. proceed to step 6. ·
6. Remove the four screws that secure the control panel to
the refrigerator and remove the panel.
7. Place the probes of the ohmmeter across both terminals
of the thermostat and then across both terminals of the snap
switch.In either case, little or no resistance indicates that the
component is functioning correctly. If there is very high or
infinite resistance, replace the faulty component
110.-Volt Operation
If the refrigerator is not cooling property while operating on
11 O volts. the following series of tests should be per1ormed to
determine where the problem exists.
Procedure
#5
1 . Remove the refrigerator from the coach; refer to
REMOVAL OF REFRIGERATOR.
2. Plug the 110-volt refrigerator cord into an altemate
110-volt socket.
NOTE: Whe.n the refrigerator is plugged in,
there should be an audible "CLICK."
If
no
"CLICK" is heard, the 110.-volt supply cord
is faulty and should be replaced.
3. Allow the refrigerator to operate for 1 to 2 hours. If the
refrigerator is cooling properly after this time, the problem lies
in the coach wiring. If the refrigerator is not cooling and the out-
side of the unit is warm, the cooling system is blocked. Refer to
Procedure #1 to correct a blocked system. If the refrigerator is
not cooling after per1orming Procedure #1, continue with
Procedure #6.
Procedure #6
With the refrigerator removed from the coach and plugged
into an alternate 1 10-volt outlet. proceed as follows:
1. Using a voltmeter set on the appropriate AC scale, care-
fully measure the line voltag·e (110-120 volts) on the red and
black lead wires of the refrigerator heater element. If no voltage
is present. adjust the thermostat control from one extreme to the
other while observing the voltmeter scale. If voltage is present
while adjusting the thermostat. proceed to step 2. If voltage is
not present. proceed to step 3.
2. Unplug the refrigerator from the AC outlet and disconnect
the red and black feed wires from the heater element lead wires.
Using an ohmmeter set on the R x 1 scale, measure the resis-
tance on the red and black lead wires of the heater element If
the resistance is not 72 ohms (..:t.3 ohms), the heater element
should be replaced.
3. If there was no voltage present after step 1, unplug the
refrigerator, remove the four screws that secure the control
panel, and remove the control panel.
4. Plug the refrigerator into a 110-volt AC outlet Using a
v.oltmeter set on the approrpiate AC voltage scale, measure the
voltage across relay contacts #8 and #11. If no voltage is
present. the relay is defective and should be replaced. If line
voltage (110-120 volts) is present, this indicates that either the
thermostat or the snap switch is defective. Check both compo-
nents with an ohmmeter. Whichever one has very high, or infinite.
resistance is the faulty component and should be replaced.
After per1orming all of the electrical tests, it may be determined
that the cooling system of the refrigerator needs replacing. In
such cases, TMC/MCI recommendsthatthe unit be repaired by
professional refrigerator service personnel.
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