Buzzing from underneath td4?

Hi guys. Suddenly got a buzzing from ubderneath my td4. Sounds like the fuel pump constantly on? I've got a FBH fitted too which also seems to do what it wants. It was on the other day when it was warm?! Any ideas on both probs?

sounds like the thermostat on the fbh and could be the fuel pump buzzing

Cheers. The buzzing sounds like the fuel pump priming when u turn the ignition on but it continues. Doesn't seen to shut up. Duff relay not shutting it off after a few seconds priming?

Runs for about 30 seconds from memory after turning the ignition on and not starting engine

FBH is controlled by a signal from the ECU, then via a temperature sensor behind the front bumper, you can see it fitted behind the lower grille.
Mine stops working at about 15 degrees, but sometimes suprises, if its sitting in the shade it may fire up on a warm day, but soon stops.

You can intercept this wire and take control of it yourself.. Its been covered on here before

That's were ya missus left the vibrator??