Relays will "buzz" if they don't have enough power... AKA: A poor electrical connection to the relay.

I would track down the buzzing noise - if a relay, unplug it from its socket and clean its electrical connections with electrical parts cleaner and a tooth brush.

Electrical parts cleaner at auto parts store.


P.S. I assume everyone knows all about these things, but suddenly realized that may not be so... But for further knowledge, a relay is like an electrically operated switch. It would "click" on or "click" off in normal operation. If it was buzzing (not working properly), it would be rapidly be turning on/off or moving the "switch lever" to almost on, then back to off again. Bottom line: It would never switch on, to in turn switch on, whatever it was supposed to switch on! (That could be the fuel pump if it is associated with those - OVP relay, fuel pump relay, or possibly something else.)