Part Identification Quiz

Hi all, i think my alternator has gone mad and need to replace, but as its a mad one off vehicle, where does this alternator originate from, rrc land rover 90/110? citroen 2cv????? all help appreciated

Looks like a Lucas, possibly a 15ACR? Take it to any Lucas agent and get an exchange one. relatively cheap to get and simple to fit. Might be worth checking the brushes, take the black plastic end off (8mm spinner or 1/4 drive ratchet) and theres 2 screws holding it in. Worn out brushes will stop it working as will knackered diodes. Why do you say its gone mad? If youre looking to get one off something scrap, it originates in lots of 70's and 80's fords. MK 2 escorts, capris etc.

when i say mad, i mean MAD! ignition on, no dash lights, fuel guage or anything, start engine same but no rev counter, rev it then all works and no charge ignition light comes on! oil pressure suddenly stopped working and everythinng, its an electrical mystery! Im hoping that the alternator holds the answers!

Hmmmm, I'm thinking voltage regulator which is in the alternator But the battery voltage should keep all the other instruments working? Have you measured the voltage across the battery and then revved it to see if the voltage increases to around 14V? this would tell you if the alternator is working.

As said above sounds like more is going wrong than the alternator... it does sound like a diode pack is not switching properly.

The battery should run everything, which clearly has enough juice in it to run some lights and guages if its starting the engine.

OK gents, cheers for replies, new alternator fitted, absolutely the same, further research has revealed the following:
NO power is getting to the instrument panel or alternator does not charge, UNTIL! place a small test lamp across the terminals of the alternator, then the alternator comes under load, light apperasas if by magic, the fact that even the oil pressure light, the simplest of circuits doesnt even come on initially tells me something. So i came to a similar conclusion, a relay or switch / diode isnt happening, but which one???? anyone got some spaghetti diagrams?
Any other advice is massively appreciated, mechanically I am more than happy, I even built the car! (RRC Chassis) but electricerry is not my science!

Sounds like you have incorrect wiring somewhere. From what I can remember you should have a +ve from the ignition supply through the lamp with the lamp -ve going to the brushes. Voltage regulator and rectifiers etc are all internal to the alternator. The alternator should have a small wire (from the lamp) and a large one going to the battery. You need to look at some basic circuit diagrams and then test your vehicle wiring.

if it works when you put a lamp across it then its a warning light fault, either the bulb is blown, you have no ign feed to the bulb/instrument cluster or the earth between the bulb and alternator is broken/loose/corroded.

As you say you have no dash at all then i'd start with the ign supply to the instruments. if you remove the cluster and look at the tracks, you should be able to work out which one is the ign feed without diagrams, it will supply all your gauges,charge and oil light

In order for an alternator to work, you need an ign feed through the bulb to the alternator.

Cheers Mr Clutchdust, that sounds to be just what i needed to know, will try it this weekend when i get home and let you know what it was, for future reference, once again, cheers All

It looks like a Range Rover, I understand you will not get a direct replacement as they are no longer made, but a similar replacement.