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StorminNorman · 03-20-2018, 07:39 PM

Do you have a 2 relay or 3 relay fan setup ?
The 2 relay type operates each fan independently. Each fan is either 100% on or off. One fan or both fans can be on if the PCM commands it. Uses 2 outputs from PCM.

The 3 relay setup runs both fans in series for low speed. Then it runs both in parallel for high speed. They always run together.
Uses same 2 outputs from the PCM.

Basically the PCM doesn't care which system you use but you have to get the relay wiring right for each type.
If your PCM was done by LT1 swap Id be surprised if it isn't done right. That guy knows his stuff

03-20-2018, 07:39 PM	#16
StorminNorman Registered User Join Date: Jul 2017 Location: Victoria BC Posts: 71	Re: PCM is not grounding fans properly Do you have a 2 relay or 3 relay fan setup ? The 2 relay type operates each fan independently. Each fan is either 100% on or off. One fan or both fans can be on if the PCM commands it. Uses 2 outputs from PCM. The 3 relay setup runs both fans in series for low speed. Then it runs both in parallel for high speed. They always run together. Uses same 2 outputs from the PCM. Basically the PCM doesn't care which system you use but you have to get the relay wiring right for each type. If your PCM was done by LT1 swap Id be surprised if it isn't done right. That guy knows his stuff __________________ 81 short step.