My experience with loose spade connectors (female) is that it is better to replace the connector rather than squeeze it with a pliers especially if it is old. The connectors get loose for a few reasons, corrosion is one and deformation due to overheating is another. You can tighten them but you may find that they loosen up again.
Make sure that you also look at the male side of the connector on the switches/breakers for corrosion and if dirty, clean them up with some emery paper. Finally AFTER reconnecting , use a protectant like Boeshield T-9.
Make sure that you also look at the male side of the connector on the switches/breakers for corrosion and if dirty, clean them up with some emery paper. Finally AFTER reconnecting , use a protectant like Boeshield T-9.