Land Rover V8 Discovery Faults

So you don't use your Landy for a little while, it may have been damp or frosty or in my case the thermastat had packed up as well. When you press the button on your remote nothing happens.
You think low engine battery, use the key in the drivers door lock and put the key in the ignition then a whole host of different problems can occure including:
Engine won't start
Immobiliser light flashing in any one of its set patterns
Central locking doesn't work
Indicators don't work
Fog lights don't work
Stange 8 or D shape with a diagnal line going through it where your gear selected should be on the dash
6 dings from the audible warning system
Indicators do work but only with driving lights on
Gear stick wont let you engage in drive
Hazard lights don't work
some windows won't work
Heated screens front and rear wont work
Heated seats don't work
Heater blower doesn't work
And possibly a few other things that you havn't pressed while trying to work out whats gone wrong!
You then go through all the motions of key in the ignition for 10 seconds, press unlock 5 times, etc with no joy. As its to early in the morning to have a beer and think about it, you google a few of the above and they seem to point toward the BCU (Body control unit) or IDM (Idiotic device managment).
BCU sounds more like the problem so you read up and find the cost of new and second hand, can they be refurbished and do they need programming. It all sounds expensive and complex so google other words in the hope of cheaper solution.
Whilst I was thinking of other faults that may give me a clue I started thinking about power. Occasionally if I pressed the heated screen you could hear a change in speed on the fan for example which would say to me power starvation somewhere.
Cutting to the chase I investigated the inside fuse box under the steering column

If you think you have a few of the problems above follow these instructions:
1) Disconnect Engine battery and any secondary batteries (Neg first)
2) Turn the 2 plastic screw 90 degrees on the panel under the steering column to get acces to the grey fuse board.
3) Carefully undo the 2 multiway plug connectors on front (they have a push in locking tab on the side)
4) Undo the 10mm nut at the top of the fuseboard
5) Lean the fuseboard towards you, the bottom is secured by a push in plastic fitting that will slide out when you have done the next bit.
6) Carefully remove the multiway plug connectors on the back of the fuseboard (locking tabs again), I number the plugs as I remove them with a permanent marker (Still an old Army Vehicle Electrician at heart) although they do look like they are keyed to be different to each other.
7) Pull the fuse box out from under the dash and inspect the connections on the back of the Fuseboard and on the multi plugs

You will probably see corrosion and water damage around the multiplugs, especially on the 3 bigger power cables going in at the bottom.
You now need to carefully take the back off the fusebox, as it has locking tabs all the way around, I put in about a dozen small screwdrivers to push the tabs in and levered the back off, you should then see water damage across the tracks on the circuit board, on mine it had even lifted the protective coating off a track but the track was OK.

You then need to carefully clean the crud away from the tracks and connectors, if you don't feel confident, ask a sparkie to do it with a diamond probe and solvent cleaner or get a second hand box off ebay for £30.
Look closely over the whole board to make certain there are no other corroded or bridged connections.
When your happy its clean, put it all back together, plug it all back in, re-connect the battery and hopefully everything should work again, including the remote locking with out having to turn the key for 5 seconds, put in codes etc.
I think the reason mine finally packed up was that my heater wasn't blowing hot air due to the failed thermastat, this resulted in condensation or maybe a leak collecting at the base of the fuse box. It no doubt would have packed up eventually, but having no warm air in the driving compartment wasn't drying out the moisture.
Anyway usual legal blunff that if you try this repair its at your own risk, but it certainly solved my electrical issues.

Use the following link for a few Land rover specialists who may be able to help if you don't fancy doing it yourself: