Fuse box making noise

Malfunctioning relay, the clicking you hear is most likely the contacts in a relay, listen closely and even place your finger on each relay one at a time until you locate the faulty one ( you should be able to feel the one that's clicking) after pinpointing which one it is, pull one of the same amperage from another location in fusebox (one for say fog lamps or horn not one that controls engine or fuel pump etc.) and put it in the location of the faulty one to test it . . . hope this helps