Fans usually cut in at 3 stages, 92*C is the first stage.
front AC fan comes on when AC is on and there's a second speed for both fans at a higher temperature. not sure what this is.
Could be worth you connecting your fans one at a time direct to the battery to see if they both work at both speeds? low speed fails first and common on any car for the resistor coil to cause this. motors can also fail, main cooling fan motor does more work than AC one so usually goes first.