In Dowsing mode, the Goddess Sword acts as a sort of compass to inform Link about nearby important items and help him track them down. Link can choose in the Dowsing menu which specific object or person he wishes to track down. When Link is in the Dowsing mode, the camera will switch to a first-person perspective and allow the young hero to explore his surroundings. As Link gets closer to the object or person he is searching for, the sword will beep faster and faster, pointing in the direction in which it is found. Fi can obtain new Dowsing targets by scanning people and objects and focusing on the aura it produces.
After Link tempers the Goddess Sword into the Goddess White Sword, its new powers can allow Link to dowse for more items. However, Fi may only store one optional Dowsing target, and if Link selects a new one, the previous target will be erased.
↑"I can lead you in the direction of this aura through a process known as dowsing." — Fi (Skyward Sword HD)
↑"It is possible to use your dowsing ability to locate hidden objects or creatures." — Fi (Skyward Sword)
↑"Furthermore, my analysis suggests that this Kikwi most likely produces a false-positive dowsing reaction due to previous direct contact with Zelda. [...] Learning that Zelda is no longer with the Kikwi elder is an unfortunate setback. But he may still have useful information. Taking this into account, I calculate an 85% probability that your quest will be aided if you find the lost Kikwis for the elder. To expedite your search for these forest-dwelling creatures, I have added Kikwis as a dowsing option." — Fi (Skyward Sword)
↑"Nayru's Flame has strengthened this blade, increasing its dowsing capabilities." — Fi (Skyward Sword)
↑"Master, the abilities of your sword have increased. It is now possible to dowse for Rupees. I have registered Rupees as a viable dowsing target. Use this exciting new feature as you deem necessary." — Fi (Skyward Sword)
↑"Your dowsing ability can be calibrated to locate the item that this person seeks. However, if you are searching for another object that someone has asked you to find, that target will be removed when you switch to this target." — Fi (Skyward Sword)