Disco 4 (LR4) battery light on

hi
having heaps of bother with my 2015 d4
battery light on
no charge voltage at battery positive
both batteries new from landrover
due to various fault codes ive fitted new battery monitor sensor and change the fuseable link on batt positive to bms
changed alternator,no different
i have no voltage down the exciter wire to the alternator when engine is running,i know that this voltage is controlled by the ecu as a signal to turn on the alternator but im getting nothing.
can anyone point me to a wiring diagram for the exciter wire please
i am getting code PO65B-16 Generator control-circuit range/performance-circuit voltage below threshold
thankyou

So basically you've fire the parts cannon before diagnosing the cause?

Graculus said:

So basically you've fire the parts cannon before diagnosing the cause?

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Yes I did like a fool,but there you go.
I've found today buy actually doing some diagnostic tests that I have no signal voltage down the exciter wire when engine is running, it's a one wire plug that according to your diagram and autodata runs directly to ecu ,autodata says pin 30 but can't locate that due to masses of wires, was wanting to do a continuity check down the wire.next job is to try and get an ecu pin out diagram.
Thanks for the info

The connectors are numbered - can't remember if on the pin or socket side.
Because it's a LIN, expect to see it fluctuating between 10-11VDC, if you get full battery voltage, it's a short to +ve
I'd also check at the intermediate connector C3069/C3070 first, if you check pin 4 on that connector, with the connector open, you should get LIN on both connectors, obviously investigate the side you don't get the correct voltage.

Graculus said:

The connectors are numbered - can't remember if on the pin or socket side.
Because it's a LIN, expect to see it fluctuating between 10-11VDC, if you get full battery voltage, it's a short to +ve
I'd also check at the intermediate connector C3069/C3070 first, if you check pin 4 on that connector, with the connector open, you should get LIN on both connectors, obviously investigate the side you don't get the correct voltage.

View attachment 332777

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Ok thanks
Getting a bit out of my remit if I'm honest, I'll try and make sense of it all but might need someone in the know to sort this now, feel free to drop by lol

linden cahill said:

...next job is to try and get an ecu pin out diagram.

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Hi, the two relevant connectors attached