2 speed fan wiring
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Teching In
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2 speed fan wiring What's the consensus of opinion regarding wiring two speed electric fans. Does one use two temperature probes, low speed on at 180 and high at 200 or use the low speed at 180 and use the AC cycle for high speed? Is there a wiring design to do both? I'm not using the PCM to trigger the fans. The set-up is a 5.3 in a Sonoma with dual fans from a Ford Contour/Mystique. The Ford set-up spins both fans for each speed but the turn on remp is controlled by the PCM.
Thanks for the help.
Thanks for the help.
Why not use the PCM to control the fans? The factory way was to run the fans in slow speed above a certain temp and in fast when a higher temp (can't remember off the top of my head) was reached or the A/C was turned on. There are three relays that control this with two lines running from the PCM. The fans run in series for slow speed, 6V.The system is much simpler than trying to use two temp probes plus the temp sensor for the PCM. I have a schematic drawing of the three relay setup if anyone wants it.
Launching!
Joined: Dec 2004
Posts: 274
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From: Kansas City, MO
Originally Posted by 70 LS1
Why not use the PCM to control the fans? The factory way was to run the fans in slow speed above a certain temp and in fast when a higher temp (can't remember off the top of my head) was reached or the A/C was turned on. There are three relays that control this with two lines running from the PCM. The fans run in series for slow speed, 6V.The system is much simpler than trying to use two temp probes plus the temp sensor for the PCM. I have a schematic drawing of the three relay setup if anyone wants it.
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Teching In
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The PCM program for the 5.3 trucks does not have a fan trigger pin like the LS1, not sure if it can be added. I'm worried the low speed may not be sufficient airflow to kee the motor cool in traffic and when towing.
TECH Resident
Joined: Jun 2004
Posts: 841
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From: Tampa, FL
The 5.3 computer CAN be modified to run the e-fans. It only turns on the low temp fan though. But this is easily made to work. Simply wire the trigger signal from the computer to turn on and off both fans at temperature. There is no "slow speed" when you do this. They are on or off.
Don't forget to wire them to the A/C also (If you are running A/C) so they will be on when the compressor is engaged.
Don't forget to wire them to the A/C also (If you are running A/C) so they will be on when the compressor is engaged.
Originally Posted by NoRotor88
70 LS1, is there any way I could see that wiring schematic? Thanks, Jesse.
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