Ls swap electric fans
Thread Starter
Teching In
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Ls swap electric fans Hi everyone I had a question that I haven’t been able to find a clear answer for.
i have a radiator with 2 single speed fans that i just installed in my LS swap. The pcm can only control the one hi fan. Can I use the trigger ground from the pcm to activate two relays and turn both fans on? Installing a jumper from one relay pcm trigger wire to the other relay pcm trigger pin? I hope that makes sense. Lol
i have a radiator with 2 single speed fans that i just installed in my LS swap. The pcm can only control the one hi fan. Can I use the trigger ground from the pcm to activate two relays and turn both fans on? Installing a jumper from one relay pcm trigger wire to the other relay pcm trigger pin? I hope that makes sense. Lol
TECH Senior Member
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From: Central Cal.
Actually, the PCM can control a relay, that with high enough capacity, can control however many fans you need.
What you need to be aware of is, that much sudden amp load is hard on the battery and alternator.
I would look into a PWM controller that would ease the fans on only as much as needed
What you need to be aware of is, that much sudden amp load is hard on the battery and alternator.
I would look into a PWM controller that would ease the fans on only as much as needed
Thread Starter
Teching In
Joined: Jan 2024
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That's because it needs to be setup in the tune properly to run Electric Fans. Then you'll have two wires to run your two fans low and high speed using the three Relay setup GM has been doing since 1995.
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Not sure what universal patcher, a tuning program? I use HP Tuners, much easier to do it with that. Just make you have the correct wires.
PCM BLUE PIN 42, Fan Low, dark green wire
PCM RED PIN 33, Fan High, dark blue wire
PCM BLUE PIN 42, Fan Low, dark green wire
PCM RED PIN 33, Fan High, dark blue wire
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Verdad Gallardo I did a little google search, seems like that program can do some stuff. Person that created it is in this Forum.
https://ls1tech.com/forums/pcm-diagn...patcher-2.html
Here's a vid I found, might help.
https://ls1tech.com/forums/pcm-diagn...patcher-2.html
Here's a vid I found, might help.
Thread Starter
Teching In
Joined: Jan 2024
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yes my fan low just makes the relay click repeatedly and the fan never comes on.
Thread Starter
Teching In
Joined: Jan 2024
Posts: 30
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I did a little google search, seems like that program can do some stuff. Person that created it is in this Forum.
https://ls1tech.com/forums/pcm-diagn...patcher-2.html
Here's a vid I found, might help.
https://www.youtube.com/watch?v=24b4g3AW37M
https://ls1tech.com/forums/pcm-diagn...patcher-2.html
Here's a vid I found, might help.
https://www.youtube.com/watch?v=24b4g3AW37M