Localization and energy efficiency is very important for UAVs. In this work, we propose a new mechanism for data routing based on localization in GPS-denied or GPS-challenged areas. The proposed mechanism relies on a weighted centroid localization technique, where the position of unknown UAV nodes are calculated using fuzzy logic. The UAV nodes are organized into clusters. The proposed localization algorithm first localizes the UAVs, then elects the next cluster head in order to minimize the energy consumption of the whole network and consequently increase its lifetime. Evaluation of the proposal shows that it is more efficient than the existing solutions in terms of energy consumption, localization accuracy, localization time, and data transmission.