2000 Discovery Electrical Problem

Td5 Discovery with an electrical fault.When switching engine off it continues to run and all the dash lights glow at you.
Sometimes it wont open the doors with remote and alarm goes off.
Sometimes with engine running and you open the drivers door main beam light will come on.
Any thoughts
Thanks.

Might be a dodgy earth

Do a quick check for water on/in the BCU.

The windscreen can leak and water ingress into the BCU.

There are two computers you will find behind the glovebox, drop the glovebox down and you will see two boxes one is silver the other black, towards the side of the car. The Black one is the Body Control Unit, the silver one is the ABS/Suspension computer. You can remove the BCU by undoing a single bolt and disconnecting the multiplugs... it's fiddley.

Check for damp in that area. The BCU controls many of the body electrics and also has a relationship with the main engine ECU