Is 'холодильнику' indeed Loc as Duo suggests as a hint? The inflection '-у' looks like DAT to me and, moreover, the dative case in Slavic can perform inessive functions, which btw is the case in this sentence. In contrast, what I usually associate with LOC would be something like 'холодильницi'. Has this "form" (ending in '-i' for m. gender) been lost universally or simply this is atypical example that employs dative /rather than "true locative"/ to indicate location?
Dative and Locative basically overlap in their form. It's a bit redundant. But it's easy to decide: if you see "on", "in", "at", "under" etc, use Locative, Locative has the same form as Dative (can't think of any time when it doesn't, anyway it's worth a bet), so just use Dative :D