Cooling fan kicking in

I'm gonna assume,

mind ya I've owned & driven a whole 2 FLD Shakers in my time that are early 90's models so,

You're run'n the engine fer AC at night?

High head pressure is commanding the fan to move air across the ac condenser.

Get a manual fan switch put in, and turn it on when you land at night. No more constant cycling on/off..

 

If head pressure is supposedly right at the high cut-on point could it possibly be a bad sensor or could there be an issue in the A/C system that is causing the pressure to stay high?

 

Ambient air temp has a hand in it too. Down here were its been in the high 90’s or around 100 and 90’s percent humidity you can start up a cold engine and the temp sensor on radiator will already cause the fan to kick on.

 

That's above my pay grade.. lol

If I stop at a red light more than a min or 2 in 85°f + weather with the ac on my fan comes on.
If I'm rolling more than 15mph, no matter the blower speed setting there is enough air flow over my condenser the fan never comes on unless the engine thermal switch commands it @200°f water temp..

My older DDEC II Detroit was a 205°f thermal switch & both acted the same other than the 5°f difference..