Tried to start my Jaguar heard a click now no power . Battery has power and power is going from trunk but no power to engine compartment area.

 

I would recommend checking the engine compartment bulkhead connector. It is on the right rear of the engine compartment. It is a large threaded post that connects the cable from the boot to the engine compartment.
Also I have attached a great guide from one of the forum members avt007. It has all of the checks necessary to track down a power problem.