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Juan Crespo
Juan Crespo, ASE Certified Technician
Category: Chevy
Satisfied Customers: 1513
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
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2002 chev cavalier 2.2 cooling fan not working relay is good

Customer Question

2002 chev cavalier 2.2 cooling fan not working relay is good and have power on three legs of it nothing on green wire open going to pcm I believe fuse are good an fan motor good can jump relay an make it run wont come on when temp gets to 225 like it should nor when ac is on atlow speed on whenpressure builds changed out temp. sensor and pig tail changed out pig tail at cooling fan and ac pressure switch an replaced pressure switch have a obd scan tool as well shows code po480 cooling fan 1cotrol circuit and trac light is on now
Submitted: 8 months ago.
Category: Chevy
Expert:  Juan Crespo replied 8 months ago.

Something is not right with the information you provide: if there was power on three legs and nothing on the Green wire, that would mean the relay is internally shorted and also that there was power on the Light Blue wire feeding the fan motor. Would you please recheck and get back to me so we can continue?

Customer: replied 8 months ago.
the blue wire has power leg 87 86 small green no power 30 an 85 big red wires nothing sorry was thinking about ac relay
Expert:  Juan Crespo replied 8 months ago.

Sorry, that's still wrong. The Light Blue wire is the one that connects to the fan motor; if it had power, then the fan motor would be turning. The two Red wires are the ones that supply power to the relay.

Customer: replied 8 months ago.
sorry they just brought car back to me, they forgot to replace the 30 amp fuse for cooling fan I have power on both red wires and nothing on green, blue wire nothing unless I place power at fan an it back feeds to the relay telling me the wire is good so its leg 30 red power leg 85 red power blue wire leg 87 green on 86 leg
Expert:  Juan Crespo replied 8 months ago.

OK. That means the onboard computer is not grounding the relay. From this point on we need a scan tool capable of reading engine data that would allow us to see if the computer is receiving a signal from the coolant temp sensor and, if it is, what the heck it's doing with that signal. Basically, it's either that or guessing, which I don't do.

Customer: replied 8 months ago.
I do have a solus ultra scan tool an have looked at the temp senor an can see were it raises above 225 no cooling fan comes on so I jump fan relay an see the temp drop to around 197 I can even command the fan on an off threw the scan tool and nothing happens green wire open nothing
Expert:  Juan Crespo replied 8 months ago.

I'm sorry, I'm not familiar with solus ultra scan tools, but if it is the equivalent of a Tech-II, then you should be able to command the fan on and see the results of that command on the screen. So...

... if it shows that is being turned on on the screen, but there's no ground at the relay Green wire, then there must be an open in the Green wire from the PCM connector C1 terminal 43 to the relay.

... if it doesn't show on the screen to be turned on, then the computer is bad.

... if it shows that is being turned on and there is ground at the relay wire, then check for power at the relay Light Blue wire. If no power there, replace the relay. If there is power on the Light Blue wire at the fan motor and the motor still won't work, then check the Black/White wire at the fan motor for ground. If ground OK, replace fan motor.

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