Page
10 of 40
Number
PM820010
HVAC: SmartAir eHVAC System
E. Linear Power Module
This module controls the amount of voltage delivered to
the evaporator blower creating variable blower speeds. It
is located in the return air in front of the evaporator coil.
Figure 5.
Linear Power Module
F. Discharge Temperature Sensor – Freeze
Switch
This sensor monitors the evaporator outlet temperature
as it enters the vehicle duct system.
Figure 6.
Discharge Temperature Sensor
G. Evaporator Blower
This blower pulls air through the evaporator coil and
blows conditioned air into the interior of the sleeper.
H. Condenser Fan
This blower draws air through the condenser coil to cool
the refrigerant flowing through the system.
Figure 7.
Evaporator Blower and Condenser Fan
I. Battery Management System (BMS)
This device monitors the auxiliary batteries for state of
charge, communicates with the EHVAC system and con-
trols the battery separator solenoid. LED light on this
device indicates power to the device and does not pro-
vide diagnostics. Power inputs to this device are fuse
protected.
If one of the BMS fuses blows, the solenoid will disen-
gage.
Figure 8.
Battery Management System
J. Battery Separator
This device connects the truck batteries to the EHVAC
batteries. When the starting batteries are at or above
13.2 volts, the battery management device will engage
the solenoid to allow the alternator to charge the auxiliary
batteries. When the voltage drops to or below 12.5 volts
the battery management system will disengage the sole-
noid to prevent the truck starting batteries from being dis-
charged below the engine start level.
