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cooling fan problem

jeepnut64

NAXJA Forum User
Location
Kelowna, B.C.
I have a '96 XJ 4.0L auto trans. everything in the system is working, but the fan will only come on if the air con. or heater is on (even if the engine is getting hot) WTF. It just started a few weeks ago. Any suggestions.
Thanks in Advance; Allan
 
Did you check your temp sensor/sender?? Fan shouldn't come on with the heater unless it's set to defrost.
 
Test your CTS, if it is out of spec the fan start--controlled by the PCM--may be late.
 
Since the auxiliary cooling (condensor fan) fan comes on with the A/C running then you have proven that the fan and fan relay work along with the fuse being good. It sounds like a bad temperature sensor, but you will need a multi meter or continuity tester to proceed further.
Remove the Coolant Temperature Sensor connector and check the continuity across the CTS terminals with the engine cold; you should read continuity. With the engine hot (the temperature reading more than 210*); the continuity should be gone.
With the engine running.... remove the connector from the CTS and the auxiliary cooling fan should start.

Hope this helps you troubleshoot the problem.
 
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