My Poor Little Green Wire - where's his 12 volts gone?

I've had a lot of electrical problems with the 300 Disco in the past week. A brief summary is...

No rev counter
No speedo
No temp gauge
No ignition switched dash lights, etc.
Frantic relay clicking underneath the dash.
Random wipers.

I posted a thread thinking it was the main ignition relay that was at fault (many thanks to Discool for his help on that thread) - http://www.landyzone.co.uk/lz/f8/od...main-ignition-relay-056700-5260-a-195979.html but now I have identified the problem - I just don't know what the cause is!!!

Underneath the dash there is a green wire which is 12v ignition switched - I know this for a fact as I tapped into this wire two years ago to feed some accessory relays and labelled the wire. After hours and hours of head scratching in the past few days I have checked it and when the ignition is switched on it only gives out 4.8 volts - when the battery is 12v+. I have run a fused wire with a switch into this green wire and everything works fine!!

The question is...

Where does this green wire go to/come from?
What would cause the wire to drop over 7 volts?



Any help would be greatly appreciated.

dead short some where

Thor1950 said:

dead short some where

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? how ,more like poor connection or poor wire

I think?? it's coming from/to the immobiliser/spider thingy I had exact same problem and ran a feed from another switched live to theis wire and cured it permanently.

jamesmartin said:

? how ,more like poor connection or poor wire

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JM like chaffed insulation along its length somewhere and grounding out. but may choice to this answer. hope solution is easy

wouldnt that either cause blown fuse or melted insulation

redhand said:

I think?? it's coming from/to the immobiliser/spider thingy I had exact same problem and ran a feed from another switched live to theis wire and cured it permanently.

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It's a Jap spec - no spider thing thank God! Where did you pick up the new connection?

jamesmartin said:

wouldnt that either cause blown fuse or melted insulation

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waving white flag:5bcheers2::5bseeya:

just uysed multimeter to find another ignition switched wire. Or there is a spare connector on the fuse box that you could tap into.

I'm guessing the first part of the circuit with a switched ignition feed is after the ignition switch?

Am I right?

i'll look & see if i have the same wire, voltage will drop due to theload of the items it supplies, the dash supply is green not saying that's wire is the one though.

I've yet to find a fuse board lay out drawing that would show the plugs and their circuit connections.

Just to the right of the round relay you can see two terminals one on top of the other the top one is an ignition switched I live don't know the loading of it but is ok for a relay, I use it to supply my bluetooth phone kit.

The lower one is an earth but that is removed when the ignition is switched on.

'Had a look and just the same it's a light wire so I would think feeds something like the radio'.

discool said:

Had a look and just the same it's a light wire so I would think feeds something like the radio'.

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Did you measure the voltage?

Mine's going from bad to worse.

The ignition switched wire has dropped to 0.11 volts when the ignition is on.

The permanent 12v wire is 4.8 volts - the battery is 12 volts+.

When I turn on and start, the alternator doesn't charge until I run a feed directly from the battery to the green wire. I've now got a permanent live wire with a switch hanging out of the dash.

I've just had my insurance renewal and my gut feeling is to gas axe the damn thing!

Yes the voltage is 11.94, and with the radio switched on 11.92.

Time for a bit of closure.....bought another multi function unit. Swapped last weekend and bingo, all sorted.


Thanks to all for the suggestions and help.