Hi. here are a few steps that will help you troubleshoot this fan issue you are experiencing.
Check for broken wires or loose connectors around the fan circuit.
Inspect connectors at the fan motor, relay, sensor or heat sensitive
switch, and the Electronic Control Module (ECM)--your car’s
computer control system. Also, make sure to check for a possible blown
fan fuse. These are common and overlooked troublesome spots that may
cause a fan to fail.
Run and bring the engine to warm temperature. With the engine running, use a voltage test light to check for power
to the motor fan. Be extra careful and make sure to keep your hands and
tools away from the belt, fan or any other engine moving parts. If
voltage is reaching the fan motor, the test light should glow.
Turn off the engine
after you see the light glow. Apply direct voltage to the fan motor
from your car battery using a pair of spare wires. If the fan fails to
operate, replace the fan motor. If the motor operates, your problem is
in the motor connector.
Locate the heat-sensitive switch or heating sensor if the fan motor
operates with direct voltage and the test light did not glow. You
should find the sensor in the radiator, engine block, or thermostat
Measure the resistance across the heating sensor with the multimeter.
With the engine at cool temperature (engine off), it should register
infinite resistance; with the engine at warm temperature (engine off),
you should read low resistance. If both readings state infinite
resistance install a new heating sensor, that’s the cause of your
Check the action of the fan relay if the heating sensor is registering
variable resistance. Your service manual should specify the power and
ground wires according to color codes and the proper way to test it. If
the fan relay fails the test replace it with a new one.
Check the connections going to the ECM after you determine the fan
relay is working properly. If you find broken wires or loose
connectors, make the necessary repairs. If you suspect a defective ECM
take your vehicle
to a service shop for a computer analysis. In most cases, the ECM is
rare to be the cause of a failing fan. The above steps should take you
to the root cause of your problem and help you fix the cooler fan.
Please rate and god bless.