Monaco 2002 Diplomat, Service Manual

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Electrical Systems - Chassis
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D I P L O M A T
9 • 2 5 1
Summer Use:
• Close all windows and vents to hot, humid outside air.
• MAX A/C and HI blower will provide quick cool down.
• Use a lower blower speed to produce cooler air.
Troubleshooting: The dash A/C/Heat system uses a combination of compressed air
(developed by the chassis system), vacuum air (developed by the vacuum
generator) and electric relays and vacuum switches. Therefore, any repair can be classi-
fied in one of five categories:
• Electrical • Vacuum • Air Conditioner • Heater • Defroster
The motorhome compressed air tank must have adequate pressure to operate the vacu-
um generator or damper doors will not function. Also, the dash A/C/Heat unit must be
switched ON to provide electric current to the relays, vacuum switches, etc. The dash
A/C and heater system should be used monthly to keep the compressor lubricated.
The following information is provided to assist in troubleshooting
common operational problems which may occur.
No Heating:
1. A/C switch is turned off.
2. Blower switch is turned off.
3. Verify the proper engine coolant level.
4. Verify that the engine is reaching operating temperature.
5. Verify engine coolant is reaching water valve attached to unit.
6. Verify operation of water valve to permit engine coolant to pass through
valve to heater core.
7. Check unit fuses.
8. Check power supply to water valve and grounding.
9. Check wiring.
10. Engine thermostat faulty.
No Cooling:
1. Check blower is operating, A/C switch is in A/C or Max position,
temperature control is turned to max cooling (blue area).
2. System fuses are not blown.
3. Condenser fan is operating.
4. Check power supply to unit and grounding of system.
5. Check wiring.
6. Coolant valve leaking.
7. Drive belt loose or broken.
8. Compressor Clutch inoperative, will not engage.
9. Expansion Valve faulty or frozen.
10. Thermostat control faulty.