Quest Minivan GXE V6-3.3L (VG33E) (2002)
Blower Motor: Description and Operation
Front Blower Motor
CONTROL SYSTEM OUTPUT COMPONENTS
Front Fan Speed Control
Component Parts
Front fan speed control system components are:
1. EATC unit
2. Front blower speed control unit
3. PBR (Potentio Balance Resistor)
4. In-vehicle temperature sensor
5. Ambient temperature sensor
6. Sunload sensor
7. Front blower motor relay
8. Engine coolant ambient temperature sensor
9. Front blower motor
System Operation
System Operation
Automatic Mode
In the automatic mode, the front blower motor speed is calculated by the EATC unit based on inputs from the PBR, in-vehicle temperature sensor,
sunload sensor, ambient temperature sensor, and engine coolant ambient temperature sensor. The blower motor applied voltage ranges from
approximately 4.5 volts (lowest speed) to 12 volts (highest speed).
To control blower speed, the EATC unit supplies a signal to the front blower speed control unit. Based on this signal, the front blower speed control unit
controls the current flow from the blower motor to ground.
Starting Fan Speed Control
Start Up From "COLD SOAK" Condition (Automatic Mode)
When the engine coolant temperature is below 50 °C (122 °F), the front blower will operate at a minimum voltage of (6 V) and the DEF mode will be
selected by the EATC unit. This operating mode will continue approximately 180 seconds under low ambient conditions. When engine coolant
temperature reaches 50 °C (122 °F) the system goes to FOOT mode and the blower speed slowly increases to the required speed based on coolant
temperature.
Start Up From Normal or "HOT SOAK" Condition (Automatic Mode)
The EATC unit should remain at the same setting as it was when the ignition switch is turned OFF. The front blower will begin operation momentarily