2002 Jaguar S-Type Electrical fault? Fuse Blown?

Diagnostics and Testing
The complexity of the electronics involved with the various electronic control modules and the multiplexed communications network, preclude the use of workshop general electrical test equipment. Therefore, reference should be made to the PDU User Guide for detailed instructions on testing the navigation circuit.
The PDU systematically tests and analyses all functions of the navigation system.
Where a fault involving the navigation system is indicated by the PDU, some basic diagnostic methods may be necessary to confirm that connections are good and that wiring is not damaged, before installing new components.