The MCI Renaissance coach has a computer-controlled climate control system. This system monitors outside temperature, inside temperature, and humidity, while constantly adjusting to provide the most comfort environment for your passengers to ride in.
The system also monitors the coach charging voltage. If the voltage drops too low due to alternator or regulator failure, the "HVAC" (heating, ventilation, air conditioning) system will begin to power down some of the components to conserve electricity. This is called "Load Shed."
If your coach's voltage drops to 25.5 volts or lower, the passenger fans will shut off. The driver's fans will continue to operate. This would be due to either an alternator or a regulator failure.
The HVAC system actually monitors the 12-volt side of the electrical system. If that power drops to 12.75 volts or lower (1/2 the 25.5V listed above) then "Load Shed" is activated. If your voltmeter is registering higher than the 25.5V threshold, yet "Load Shed" is activated, test the voltage on each battery individually while the coach is running. The measurements should be within .5 volt of each other. Any difference greater than that would signify a failed battery equalizer.
In summary, if the passenger fans on your Renaissance stop & the driver's fans continue running, the HVAC system probably has gone into "Load Shed." If this occurs, check the voltmeter on the dash, and the individual voltages of the batteries. Depending on the readings, these tests will tell you whether you have alternator/regulator problems or the battery equalizer has failed.
Motor Coach Industries - A New Flyer company: Corporate Address 200 East Oakton Street, Des Plaines, Illinois 60018 | Phone: 866-MCICOACH
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