The Air Conditioning compressor will make a clicking sound when it starts and stops the compressor.
Relays, in the under hood fuse box will also make a clicking sound like a turn signal.
If you have a solid wood or metal rod ( a broom stick works great) you can put it next to your ear and use it like a doctors stethoscope to determine where the clicking is coming from.
When you hit the right component or spot, the clicking will become loudest, try it.