2005 Citroen C2 L Electrical Issues

[L_Downer]

Just confirm you are measuring the positive here?
If you are & still getting no voltage move the negative lead of your meter directly on to the batter negative terminal & see if you get a reading.

No, I had the positive end on the battery itself, and the negative on the alternator...

I'll do this tomorrow...

[Paul-R]

No, I had the positive end on the battery itself...

To confirm, on the positive terminal of the battery?

...and the negative on the alternator.

Whereabouts on the alternator?

[L_Downer]

Yes, on the positive terminal on the battery... where tou would connect a positive jump lead....

The negative was on the casing on the alternator, as stated on the instructions.

[wheeler]

Yes, on the positive terminal on the battery... where tou would connect a positive jump lead....

The negative was on the casing on the alternator, as stated on the instructions.

Even doing it this way you should still get the same as what the battery is reading, just make sure the bit of the casing you are touching the negative lead of your meter to is nice & clean metal, the casing can get oxidisation on it, give where you are taking a reading a scrape with a small file or emery paper to ensure a good electrical connection

[wheeler]

Meter leads across the 2 battery terminals = battery voltage
Meter positive to battery + terminal & meter negative to alternator casing = battery voltage
Meter positive to alternator positive connection & meter negative to battery negative terminal = battery voltage
Meter positive to alternator positive connection & meter negative to alternator casing = battery voltage
If the wiring is good all these scenarios should give the same voltage reading on your meter.

Repeat the last scenario with the engine running & if the alternator is working you should get over 14v

[L_Downer]

OK, I've done some more tests, results as follows:

Battery Voltage (Resting) 12V
Battery Voltage (Running - Just Started) 11.4V
Battery Voltage (Running - Engine Warmish) 11.2V

Alternator Voltage (Positive Alternator connection to Alternator Casing) 3V

Alternator Voltage (Positive Alternator connection to Alternator Casing once Engine Warmish) 2V

All Signs point to Alternator... I'll get this sorted. Would this really cause everything else that's gone wrong at the moment though, or could there be something else at play?

[wheeler]

Even if the alternator is not charging you should still be getting the same voltage reading at the battery as what is at the alternator.

[L_Downer]

Even if the alternator is not charging you should still be getting the same voltage reading at the battery as what is at the alternator.

OK... What could this imply is the issue then?

[wheeler]

Meter leads across the 2 battery terminals = battery voltage
Meter positive to battery + terminal & meter negative to alternator casing = battery voltage
Meter positive to alternator positive connection & meter negative to battery negative terminal = battery voltage
Meter positive to alternator positive connection & meter negative to alternator casing = battery voltage
If the wiring is good all these scenarios should give the same voltage reading on your meter.

Repeat the last scenario with the engine running & if the alternator is working you should get over 14v

Do all the scenarios above & note which ones do not give the same as the battery voltage.
The big terminal on the alternator is directly connected to the battery positive & the casing is connected to the negative hence the reason you should get the same voltage reading direct at the alternator. If there is a difference (and assuming you are making good & correct connections) there could be an earthing issue.
Do you have jump leads? if so take the black one only & connect one clamp to the battery negative terminal & the other one to a good bare metal bit of the engine (engine mount bolt is ideal, see pic).
once this is connected re check the battery voltage with the engine running.

[L_Downer]

Meter leads across the 2 battery terminals = battery voltage
Meter positive to battery + terminal & meter negative to alternator casing = battery voltage
Meter positive to alternator positive connection & meter negative to battery negative terminal = battery voltage
Meter positive to alternator positive connection & meter negative to alternator casing = battery voltage
If the wiring is good all these scenarios should give the same voltage reading on your meter.

Repeat the last scenario with the engine running & if the alternator is working you should get over 14v

Do all the scenarios above & note which ones do not give the same as the battery voltage.
The big terminal on the alternator is directly connected to the battery positive & the casing is connected to the negative hence the reason you should get the same voltage reading direct at the alternator. If there is a difference (and assuming you are making good & correct connections) there could be an earthing issue.
Do you have jump leads? if so take the black one only & connect one clamp to the battery negative terminal & the other one to a good bare metal bit of the engine (engine mount bolt is ideal, see pic).
once this is connected re check the battery voltage with the engine running.

I will try and check these tomorrow, however I don't believe there is an earth as tested continuity between Battery - and Engine Block, with the resistance being very low.

I am becoming tempted to just pay somebody to sort it...

[ozvtr]

The big terminal on the alternator is directly connected to the battery positive

Just to be pedantic, the connection from the alternator to the battery is in 2 parts. Alternator to starter then starter to battery. The two leads are bolted back-to-back on a stud of the starter solenoid and retained with a nut.
Might be relevant if that nut were to come loose.
Just my 2 cents.