Socarco,
if you haven't re-jigged things behind the instrument panel, the circuit which is causing you problems should have up to 8 items connected to it.

These are the fuel gauge, windscreen wipers, direction indicators, voltage regulator, voltmeter?, oil pressure warning light, brake fluid warning light and choke warning light.

If you take Ipgo's advice and bridge the fuse box terminals with a light, it shouldn't take long to isolate which of the above is at fault...

Btw, did you cut into the wiring loom and extend the wires in order to fit fuses for the headlights?

ken.

Update to All.
No I didnt modify anything for the headlite fuses.
I changed to modern fuses due to inability to find original fuses here(Italy)
I have followed the advice for locating short with a lite instead of blowing fuses.
I found the Mauve wire coming from the ignition switch was grounded.
This wire disappeared into a bundle behind the panel.
I rugged a jumper from the ignition switch directly to the fuse box and found there was no power to the panel, wipers, etc.So, inside that bundle behind the panel there mist be connections that I cant see. (Here a schematic would be very useful, but ther aint one!!!)
My question now is. Do I need to makeup a new wire loom and replace all connections that used the mauve color code wiring?

Socarco,

some of the earlier wiring diagrams for dyanes and amis had the schematic ie a picture of the loom as if it were laid out on a table, obviously there are going to be a few differences to your exact model but much of the dash switch gear is the same - the looms all share the same DNA

And which colours are you colour blind to? the mauve and browns can be difficult to tell the difference even to us with good colour vision. browns are always earths and are usually the opposite way to feeds so there is a possibility youve plugged a live feed for something into an earth?- borrow a helper to tell you what colour is what?

Ive also gone through all my wiring diagams and coloured them in-it helps ....but not if you cant see the colours

Are we making any progress? Yes And No
First Off, Sean, I'm not color blind, you must have mistaken some comment.
I seem to be getting somewhere but then maybe not. I have reattached the Mauve lead to the ignition switch having changed nothing and
1, The following now work except at reduced voltage (The test bulb, however is bright as ever) Wipers, oil pressure lite, choke lite, brake fluid test light.
2.The following do not work, Mauve connection to fuel ga. and mauve connection to the ameter ,grounded, so they are presently disconnected. No voltage to panel lite and only 6V to the flasher which probably accounts for the turn signals not working.
3. Have checked all mauve circuits, none are reversed.
4. When I turn on ignition, the lights that work are bright but immediately dim. (To about 6v)

There seems to be an old adage that if something doesnt work, take it apart and put it back together and it will probably work. Not always true however.

Sorry mate thought it was you who said you were colour blind...must have been someone else somewhere else.My apologies.
reduced voltage because its being fed via the resistor that is the lightbulb.
you just have to persevere go over every circuit from battery to the earth eventually its the bit that you thought it couldnt be, you were sure it was right and you think "Doh! how did I miss that"

I hate electrical problems

If the light goes off when you disconnect the Mauve wire - this is the source of the next search

This cable will have several more branches on it and I have seen looms where there are additional crimps inside the loom.
The idea is to disconnect wires in the circuit till the light stays off - Once isolated wires that have been disconnected can be refitted with the light staying off.
If you can't isolate in a logical way - then next step is to start unwrapping the insulation on the loom until you come to a branch on the suspect wire and start isolating at this location.
Wires can then be reconnected and if the consumer unit is not switched on the light will stay off.
Like Sean said the voltage is reduced as the light bulb is acting as a resistor in series with the circuit - voltage to consumers will only return to normal when the fuse is refitted

Have you tried disconnecting the voltage regulator? - three pin connector near battery. On my schematic this has a feed from the Mauve wire from the ignition switch. - Read thread again Ken had already seen this one

Thanks Nibby.
You have brought up a good point. I disconnected the D+ terminal on the regulator which is coded "blue". The light went out. Now I'm not sure where the blue goes. Is it connected to the mauve circuit? I checked the regulator which is good.
You said you had a schematic. Can you post it?

I have not checked but surely the regulator must draw some current. If it draws current it will put an earth path on the bulb and light it up.
Does the fuse still blow with this wire removed? If not I would say this could be the problem.
If it does then the regulator has been leading you a merry dance and you will have to continue isolating wires until the light goes off and you are able to refit the fuse without it blowing.

Well, Guys, The ordeal is over---almost.
The problem: Some SOB previous fiddler had completely mixed the wiring behind the panel.
Hot leads to wrong places, instruments grounded and some add on switches and indicator lights. The presence of a spare green and brown lead didnt help.(still unidentified)
Everything electrical is now back in the proper place

The only thing left are the turn signals and for that I hope not to need to remove the bloody panel again.

Thank you all for your encouragement and suggestions. They all helped.
I am very impressed with the interest and patience of the participants of the Forum.
Keep up the good work!!!