Are you talking about turn signals? Your question does not make that clear. In any case, to the best of my knowledge there is no way turn the turn signal "click" off. Furthermore, I don't understand why one would want to turn the "click" off.

 

I don't know but assume that the turn signal "clicker" in todays cars are some sort of solid state device. In older cars there was a turn signal relay which was intentionally designed so you would hear the relay make/break contact thus the clicking sound. There were different sound level relays that you could buy to either increase or decrease the noise but there was always a sound. So if there is a replaceable relay in the Jag system I would suspect you could get a more silent relay.

 

There is a speaker on the circuit board in the instrument cluster for the indicator ticks. It's known for this speaker to fail, and no ticks anymore... happens in the XF as well. Dealer will tell you a replacement instrument cluster is needed, but anyone good with electronics is able to replace it with a steady hand and a soldering iron.