Chevrolet Sonic Repair Manual: Cooling Fan Description and Operation (LWE, LUW)
System Overview
The engine cooling fan system is composed of one cooling fan, 2 relays, the engine control module (ECM), and the associated wiring. The cooling fan assembly includes 1 resistor mounted in the cooling fan shroud. The cooling fan resistor may be a stand alone component, or a part of the cooling fan motor and harness assembly. This combination of components enables the ECM to operate the cooling fan at 2 speeds using two fan control circuits. The ECM will operate the cooling fan at either Low or High speed based on the cooling requirements.
Low Speed Operation
The ECM applies ground at the FAN 1 control circuit for the coil side of the low speed cooling fan relay. The energized low speed relay switch closes to supply B+ through the cooling fan resistor, to the engine cooling fan motor. The result is cooling fan operation at a reduced speed.
High Speed Operation
The ECM applies ground at the FAN 2 control circuit for the coil side of the cooling fan high speed relay. The energized high speed relay switch closes to supply B+ directly to the engine cooling fan motor, by-passing the cooling fan resistor. The result is cooling fan operation at full speed.
Cooling Fan Description and Operation (LUV)
The engine cooling fan system is composed of one cooling fan, a series of 5 relays,
the engine control module (ECM), and the associated wiring. The cooling fan assembly
includes two resistor ...
Engine Coolant Fan Shroud Replacement (LDE LUW)
Engine Coolant Fan Shroud Replacement
Callout
Component Name
Preliminary Procedure
Remove the radiator surge tank. Refer to Radiato ...
Other materials:
Wireless Communication Interface Antenna Replacement
Wireless Communication Interface Antenna Replacement
Callout
Component Name
Preliminary Procedure
Remove the communication interface module. Refer to
Communication Interface Module Replacement
1
...
Brake System External Leak Inspection
Warning: Refer to Brake Fluid Irritant Warning.
Caution: Refer to Brake Fluid Effects on Paint and Electrical Components
Caution.
In order to inspect for external brake fluid leaks, first inspect the fluid
level in the master cylinder.
While a slight brake fluid level drop c ...
Battery Inspection/Test
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic
procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic
catego ...
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