Cooling fan on constant?
05-13-2010, 04:01 PM
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Car: 1986 Iroc
Engine: 5.0
Cooling fan on constant?
My cooling fan runs constant. I've just changed the Temp sensor! It's still running? anyone got an idea why.
05-13-2010, 04:03 PM
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Car: Trailblazer EXT 4.2 (Firebird Form)
Engine: 5.1 4bbl
Transmission: 700R4 Mega Raptor Level 4
Axle/Gears: 2.73
05-13-2010, 04:17 PM
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Car: 1986 Iroc
Engine: 5.0
Re: Cooling fan on constant?
Maybe, but the relay only clicks on when the car is started. then only switches back off when the engines cut. Will it still do this if its shot?
05-13-2010, 04:21 PM
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Car: Trailblazer EXT 4.2 (Firebird Form)
Engine: 5.1 4bbl
Transmission: 700R4 Mega Raptor Level 4
Axle/Gears: 2.73
Re: Cooling fan on constant?
well let's see... I could be wrong...
but the fan switch is the ground side of the relay, the temperature switch reports to the ECM of the current temps, then the ECM sends a 12v signal to the relay to close and therefore sending juice to the fan... am I right...
so with that being said, if you already replaced the fan switch then you should check to see if your temperature sensor is closed...
but the fan switch is the ground side of the relay, the temperature switch reports to the ECM of the current temps, then the ECM sends a 12v signal to the relay to close and therefore sending juice to the fan... am I right...
so with that being said, if you already replaced the fan switch then you should check to see if your temperature sensor is closed...
05-13-2010, 11:04 PM
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Car: 87 Formula/ 00 Xtreme
Engine: TPI 305/ v6
Transmission: struggling t-5/ 4l60E
Axle/Gears: 3.08/ 3.23
Re: Cooling fan on constant?
You are not totally wrong. There is no fan switch on an 86 with single fan (that's all there was). Also, the ECM provides ground to the relay, not +12v.
There is an a/c line on the passenger side frame rail (aluminum) with a 2 wire plug on it (blue and black wires), unplug it and jump the plug terminals. If it solves the fan issue, the fan pressure switch on the line is bad (no longer grounding).
No-A/c vehicles had the blue wire grounded, if the blue wire is left open (no ground), the fan will run as soon as the ignition is keyed on.
There is an a/c line on the passenger side frame rail (aluminum) with a 2 wire plug on it (blue and black wires), unplug it and jump the plug terminals. If it solves the fan issue, the fan pressure switch on the line is bad (no longer grounding).
No-A/c vehicles had the blue wire grounded, if the blue wire is left open (no ground), the fan will run as soon as the ignition is keyed on.
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