New bilge pump buzzer playing up erratically

[sailor Martin]

Hi

I just installed a "3-24v" buzzer on my 24v system.
Everything was working fine up untill a few days later. The buzzer started sounding a strange high pitched sound. The sound changes or even stops when you move the buzzer around. I have tried replacing the buzzer with a different brand but still it's a "3-24v" buzzer. Sound came back after a few days.

What would cause this?

These are all sort of wires near the buzzer. Can they cause this somehow? I can draw an electrical diagram if necessary.

Cheers
Martin