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T--326
There will be some applications where the switch mounting plate,
thermostat and fan speed switch are mounted in the drivers area
without the control panel housing.
On other applications the vehicle manufacturer (OEM) will supply
different type controls for the air conditioning system. Refer to OEM
technical manual for operating instructions.
2.2.1 Fan Speed Switch (three speed or variable)
Turning this switch clockwise will energize the evaporator and
condenser fan motors. The compressor clutch will also be
energized if the thermostat calls for cooling (see thermostat control
operation).
Three Speed --
The standard fan speed switch has four settings,
Off (0), Low (1), Medium (2), and High (3) speed operation. This
switch controls the operation of the system and the evaporator
blower(s) by energizing the appropriate circuits and relays located
on the electrical control panel.
Variable Speed --
Certain applications may be fitted with a variable
speed control switch instead of the standard three speed switch.
This switch controls the speed of the evaporator motors by varying
the supply voltage.
2.2.2 Thermostat Control
The thermostat controls the temperature within the passenger
compartment by switching system components on and off.
Rotate the potentiometer switch knob to the right (clockwise) for
maximum cooling. Rotate the potentiometer switch knob to the left
(counterclockwise) for less cooling.
2.3 DRIVER’S CONTROL PANEL -- FLORIDA (TEMPCON)
This control panel (See Figure 2-2) is normally used in school
buses located within the state of Florida, but not limited to that area.
This controller is wired to an electrical control board.
The controller consists of:
a. ON/OFF Switch
b. Fan Speed Switch
c. Potentiometer
d. In--Line Fuse (Behind Controller)
2.3.1 ON/OFF Switch
Power is supplied to the controller, through an in--line fuse (see
Figure 2-3) from a 12 VDC ignition source originating from the
vehicle. The controller will not operate until the ignition switch is
activated.
