3 Fan Relay + VA - Diagram

[TA_C10]

Yep, your right, I see it now... Back to original

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[dayj1]

Originally Posted by TA_C10

Yep, your right, I see it now... Back to original

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One other thing regarding your 10 amp circuit that you're using for the relay triggers is to make sure that you use an ignition circuit instead of a battery (always on) circuit. It doesn't matter when you're only using the PCM for fan control. But, when you add the trinary switch, it can turn on the fans when the vehicle is off if the coil power is connected directly to the battery. I've wired a few dozen LS swaps over the years and I've personally had 3 or 4 trinary switches go bad and stick shut. That'll activate your fans and run your battery down.

[TA_C10]

Originally Posted by dayj1

One other thing regarding your 10 amp circuit that you're using for the relay triggers is to make sure that you use an ignition circuit instead of a battery (always on) circuit. It doesn't matter when you're only using the PCM for fan control. But, when you add the trinary switch, it can turn on the fans when the vehicle is off if the coil power is connected directly to the battery. I've wired a few dozen LS swaps over the years and I've personally had 3 or 4 trinary switches go bad and stick shut. That'll activate your fans and run your battery down.

Good info, when you look at the GM official diagram it says battery positive. But they didn't use trinary switches either so thanks for that info I'm going to double check and see what I did.