The fan's on my 1991 Buick park avenue don't cut on even when my car is clearly hot they won't kick on where should I look to resolve this issue? Thank you

Next time you have the engine warmed up, turn on the A/C and see if the fans kick on. If they do, you should be fine. As long as your engine temp is staying within the normal range, you should be okay. Just for a quick test, unplug the wires on the top of the Engine Coolant Temp sensor. Pretty sure that will make the fans kick on. The fans actually kick on by the cars computer on your model. It gets readings from your Engine Coolant Temp sensor that should be located right by the thermostat.