A/C blower stays on all the time but heat and cold work when thermostat sends signal; how to fix?
What happens when you disconnect the G thermostat wire at the unit?  If your problem goes away the problem is either the thermostat or the wires. If it goes away reconnect the wire and disconnect the G wire at the thermostat. If the problem comes back it is in the wire if it stays fixed it is in the thermostat. If neither works it is in the package unit. Some units run the fan to alert you to a problem but usually that is all that will work. Older units may have a separate blower relay but most newer ones will have the relay in the circuit board. You didn’t say if this has always happened or if it just started. If it has always been that way the motor may have been directly wired to line voltage. Maybe the relay broke and they didn’t want to replace the circuit board? Or maybe someone just wanted continuous fan.