Fan wiring
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From: Russellville, Arkansas
Fan wiring Putting a 5.3l into a 64 chevelle. Had the PCM programmed for 2 fans using pin 42 blue and pin 33 green.
If I understand correctly the PCM supplies ground to the these pins when it wants to turn on the fan(s). Therefore I need to wire the releys in a "ground to turn on" circuit, not a "power to turn on" circuit.
The reason I am confused is that the conventional wisdom seems to be use three relays to do this, but looks to me like two will work just fine. I suspect I am missing something and want to find out now rather than later.
Also I am not running A/C at this time, and the two fans are each one speed, PCM set to turn on 2nd fan at a slightly higher temp than the first fan.
If I understand correctly the PCM supplies ground to the these pins when it wants to turn on the fan(s). Therefore I need to wire the releys in a "ground to turn on" circuit, not a "power to turn on" circuit.
The reason I am confused is that the conventional wisdom seems to be use three relays to do this, but looks to me like two will work just fine. I suspect I am missing something and want to find out now rather than later.
Also I am not running A/C at this time, and the two fans are each one speed, PCM set to turn on 2nd fan at a slightly higher temp than the first fan.
Go to my website.
http://ls1tuningguide.com/tuninghelpfiles.php click the link at the bottom, GM PCM Pinouts and Schematics, that link takes you to a website that has all of the GM schematics.
Find the 1999-2002 LS1 PCM schematics, once there, click the Engine Cooling Schematics.
These are the 2002 F car, three relay system. I think this is what you are after.
http://ls1tuningguide.com/tuninghelpfiles.php click the link at the bottom, GM PCM Pinouts and Schematics, that link takes you to a website that has all of the GM schematics.
Find the 1999-2002 LS1 PCM schematics, once there, click the Engine Cooling Schematics.
These are the 2002 F car, three relay system. I think this is what you are after.
