Most Amazon Fire tablets and phones have a simple setting in the main Settings app that allows you to either enable or disable location-based services. If your device has an Applications list in this menu, you'll want to make sure that location services are enabled for MapQuest and the web browsing app you use in addition to enabling them for the device itself.
To learn more about location services on your Amazon device, please feel free to read through this help article: https://www.amazon.com/gp/help/customer/display.html?nodeId=201604200