I have been investigating the reason my rear wash doesn't work so I've had the bonnet up and I've been playing with the pump, one way valve and dissasembled the rear end etc, all the usual checks, but now all of a sudden, when I turn the key, nothing happens, no lights come on the dash al all, when I turn the key back and remove it the speed momentarily goes to 80mph, then drops back to zero? It was fine just a moment ago!

Any suggestions, I'm really panicking now!

sounds like a short circuit (possibly at the pump?) or a blown fuse (check main ignition fuse in engine bay)

the interior light comes on....

interior light is not fed by ignition live, thats why it works before you switch ignition on

check the ignition fuse in engine bay.

which is the main ignition fuse?

in the engine bay there is a fusebox at the back right (when looking in engine bay). there is a single phillips screw on the top holding the black plastic cover on. remove the screw and cover and check all the fuses in there just to be sure.

All the fuses seem fine (visually - have no meter), I have now noticed that the airbag warning light comes on (and stays on) when I turn the key, still when I return the key back to the off position the speedo momentarily goes to 80, then back down, every time. Also the central locking works intermitantly.

As I have been working on the rear wash all day and have had the key in for long periods for testing, with the boot open, is it possible that I have drained the battery?

yes its possible that the battery has been drained. since you dont have a multimeter you cant check the battery but the airbag light is a good clue that insufficient voltage is coming from the battery. unfortunately the airbag ecu will have logged the fault and will now keep the airbag light illuminated until it is reset (£65 @ dealer). a short circuit is also still a possiblity.

if you have some jump leads i would try using them.

I found my multi-meter (knew it was hiding somewhere) and the battery is indeed looking flat at 10v.

Does this mean that the airbag is non-functional now, or is it just that the warning light will stay on as I can live with that for now?

depends who you ask. i've had one dealer tell me the airbag will work unless the airbag light flashes constantly, i've been told by another dealer that the airbag light will not work if the light stays on.

personally i dont know what to believe, but i know my airbag light has been removed and the wiring has been chopped and it felt so good doing it. it may not feel very good in a collision.

ok, I have a battery charger, but I'm little concerned about disconnecting the battery do do this, I read in another post of yours that I should disconnect the battery before attempting to recharge it, but further up in the thread you say that doing so can reset the ecu (is thats a bad thing). What are the implications of this and what is the best way to go about it. Thanks for all your help jug, you have been a star! Sorry, I'm such a nervous chap right now!

resetting the ecu isnt a problem, you may find that the idle is high for a few minutes when you reconnect the battery, but once the ecu has relearnt its operating parameters it will be back to normal.

get it charged