According to what I have been told the 'clicking noise' is generated from the same sounder/loudspeaker in the BSI which provides the various warning chimes. Maybe I'm wrong. When I was looking at fitting LED indicator lamps
I asked my local Citroen approved repairer where the indicator relay was and much to my surprise I was informed that it is an electronic relay* with no mechanical components and is part of the BSI ( *transistorised 'flip-flop' circuit?). cratch: