Vectra b brakes now have buzzer

cav24v

In the last few weeks a buzzer has started going off when I press my brakes.
I have traced it to a module in the 1st aid place which states it is a anhanger module.
I assume this is some thing to do with the tow bar electrics.
I'm wondering why it has started working now,why you would need it & if it can be turned off.
I could live with it as it's not loud.
Could this be why my reverse lights don't work,this is the 2nd Vectra I've had with a towbar where the reverse lights don't work!

cav24v

I guess I should've mentioned that it does have a removable towbar with plug for the trailer electrics.
The wires to the module & there is a relay there as well all look good & are not loose at all,& just to be clear the buzzing is coming direct from the module & it's just like the buzzer that tells you if you have left the lights on or if you have left the keys in the ignition.