300E 4MATIC (124.230) L6-3.0L (103.985) (1990)
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Blower Motor: Description and Operation
Blower
PURPOSE
The blower regulation system permits continuous blower speed regulation.
LOCATION
The blower function switches are located on the ACC control panel.
CONSTRUCTION
The blower regulation system consists of the ACC control unit, the blower regulator and the blower motor.
OPERATION
The blower regulator is connected to the main fuse box and ground. With the ignition switch "ON", the blower regulator is supplied with battery power.
Depending on the function selection of the blower switch, the ACC control unit continuously sends a control voltage of between 0.4 to 9 volts to the
blower regulator. As a result, the blower regulator supplies a current between 2.0 to 28 amps to the blower motor, regulating the blower speed.
Blower Function Switches
CONTROL VOLTAGE AT VARIOUS SELECTIONS OF THE BLOWER SWITCH
With the automatic function selected, the control voltages are influenced by:
^
The nominal and actual values of the interior temperature (via the interior temperature sensor and the temperature selector wheel).
^
The outside temperature (via the outside air temperature sensor on the blower housing).
^
The operating condition of the system (heating or cooling).
^
The coolant temperature.
