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It is snowing here so I thought I would work on a couple indoor projects, one of which is wiring up the fuse block and relays for a 2 speed fan controller. These are the two diagrams I found, both look to be the same. I thought at one point I found a way to do this with only 2 relays, but that may have been a fever dream. I bought a $80 C5 cooling fan from Rockauto along with the pigtails but I do not see anywhere that the polarity is marked on the fans or the pigtails, is there a standard for which pin is which?
You didn't say what ECU you are running, going to assume a stock GM. The output is always ground from them. Here is a post with the schematic, just apply voltage and make sure the pull and don't push. If they push reverse your wires you're not going to cook them.
You didn't say what ECU you are running, going to assume a stock GM. The output is always ground from them. Here is a post with the schematic, just apply voltage and make sure the pull and don't push. If they push reverse your wires you're not going to cook them.
Thanks. I am running a stock 2002 LS1 ECU and I understand the signal for the fan is ground. I will go out and apply 12 volts and see which way they spin.
02-07-2021, 10:17 AM
LS Swap 2-speed fan wiring
