Land Rover Repair: P38 No Dash lights at all - no ignition - no HEVAC - no brake pump, obd ii connector, diesel type

Question
1996 4.6 petrol Auto. On return to the car I can unlock the door with key and the plip. Put key in ignition switch and get KEY IN IGNITION on the message display plus the mileage with two beeps. Things that work are, radio, windows, central locking lights internal and extenal. But No dash lights at all (except message display)no brake pump, no gear selector lights (and able to move that), no HEVAC. Just a click from the BeCM no blowers but I can feel the relays pulling in?. I have checked everu EARTH position I can, I have changed the engine bay fuse box and put in a new large capacity diesel type battery. New ignition switch (both parts - one from Land Rover coded). Test book can talk to the BeCM but not any other ECU including the Engine ECU. But by jumping the ignition relay testbook can talk to the engine ECU but it fails to learn security - jumping the ignition relay only provides power to one side of the engine ECU - thats as far as I have got, but very stumped! any help apreciated - if I could get to a dash lights on on position II of the ignition switch test book could probably do its thing

Answer
You clearly have a power distribution problem.  Go to www.landrovertechinfo.com for wiring diagrams for your vehicle.  You'll have to pay for access but there's no other answer unless you find a RAVE CD to use.

Anyway, one of the diagrams is titled Power Distribution.  Follow the "key on" power distribution.  I think you'll find the ignition switch is bad, or there are problems you didn;t see in the connectors under the fuse box, or problems in the cables around the battery and alternator.

Whenever you can't talk to systems with Testbook it's a sign those systems are not getting powered up, or there are cable problems at the OBD II connector itself.  Pull the connector down and check it as that wiring can corrode from windshield water leakage.