https://www.lsenginediy.com/upgradin...ric-fan-guide/
Will the PCM be Required to Controlthe Electric Fan(s)?
Many owners operate electric fan(s) independently of the PCM by triggering a relay through either the A/C compressor clutch circuit or through a trinary pressure switch.
One drawback to these methods when using Gen III PCMs is that unwanted DTCs set as the PCM detects the fan(s) have turned on during conditions that the PCM has determined the fan(s) should be off. One solution is to simply disable these DTCs, which also disables the intended function of the DTC processing. A better solution is to use the PCM’s A/C control functions to gain improved A/C system control and A/C system diagnostics. (See Chapter 11 for more about A/C control.)