1995 Grand Prix cooling fan #1 runs after engine shut down

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1995 Pontiac Grand Prix SE 4D sedan 3.1L M code VIN, 80,000 actual miles.

I had to R&R the ECM because pin B1 ckt 473 would not drive to ground to activate fan #2 relay. Fan #2 would not operate at all with AC on but it does now that the ECM is changed.

Now fan #1 continues to run after engine shut down. Didn't do this before the ECM change but could have been due to the defective ECM. Is this normal for a 95 Pontiac Grand Prix 3.1L and if so how long should fan #1 continue to run after engine shut down, 2 minutes, 5 minutes, 30 minutes? Anything more than a couple of minutes seems excessive to me. The longest I've let it run is 5 minutes.

If I turn the ignition switch to the on position and back off after shut down the fan will turn off.

The new ECM was flashed with the correct program by NAPA prior to replacement.

Any ideas? Temp gauge seems to indicate normal and no overheat issues.