Chevrolet Sonic Repair Manual: 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 resistors. This combination of components enables the ECM to operate the cooling fan at 3 speeds using two fan control circuits.
Low Speed Operation
The ECM applies ground at the FAN 1 control circuit for the coil side of the cooling fan relay. The energized cooling fan relay completes a ground, through the switch side of the relay, for the coils of the cooling fan low speed relay and the cooling fan speed control relay. The speed control relay activates and supplies B+ to the coil side of the cooling fan high speed relay. The high speed relay remains inactive because the ECM is not commanding the FAN 2 control circuit ON. The energized low speed relay switch closes to supply B+ through the internal low speed resistor of the engine cooling fan motor. The result is cooling fan operation at a reduced speed.
Medium Speed Operation
The ECM applies ground at the FAN 2 control circuit for the coil side of the cooling fan high speed, and medium speed relays. The high speed relay remains inactive because the ECM is not commanding the FAN 1 control circuit ON. The energized medium speed relay switch closes to supply B+ through the internal medium speed resistor of the engine cooling fan motor. The result is cooling fan operation at a medium speed.
High Speed Operation
The ECM applies ground at the FAN 1 control circuit for the coil side of the cooling fan relay. The energized cooling fan relay completes a ground, through the switch side of the relay, for the coil of the cooling fan speed control relay. The energized speed control relay switch closes to supply B+ to the coil side of cooling fan high speed relay. Simultaneously, 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 fans internal resistors. The result is cooling fan operation at full speed.
Radiator Fan
...
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
1̴ ...
Other materials:
Airbag Readiness Light
This light shows if there is an electrical problem with the airbag system. The
system check includes the airbag sensor(s), passenger sensing system, the pretensioners
(if equipped), the airbag modules, the wiring, and the crash sensing and diagnostic
module. For more information on the airbag ...
Hazard Warning Flashers
(Hazard Warning Flasher): Press
and momentarily hold this button to make the front and rear turn signal lamps flash
on and off. This warns others that you are having trouble. Press and momentarily
hold again to turn the flashers off. ...
Flushing
Special Tools
BO 42220 Universal 12V Leak Detection Lamp
GE 41447 R-134A A/C Tracer Dye Box of 24
GE 45268 A/C Flush Adapter Kit
For equivalent regional tools, refer to Special Tools.
Note: Flushing with the ACR 2000 is not intended to remove metal from
the A/C ...
0.0059