Why won't my car key unlock my glove box for the Kia Amanti?

Make sure you are not using the valet key. Amanti's come with a set of keys (2) that can unlock everything, driver's door, glovebox and trunk lid. There is also a third key designated for valet use, allows you to disable trunk release and then lock glove box with master key. This way the valet cannot look throughout the trunk or glove box but he can lock the car and start it.