Charge light on series 3

Hi, my diesel series 3 swb charge light is turning on I'm not sure if it's supposed to as I've read its not supposed to but very few say it's supposed to be. The pictures are before the soil wire was added video is no working

I've put a new wire in with no joins and cleaned the alternator terminals. The previous owner did replace the crossmember and bulkhead outrigger but light didn't come on until I wired in a the correct horn and is earthed to the battery
(used to be an air horn from the battery)

Check for voltage down the charging light wire with ign on but engine not running, then check for volts at the battery with the engine running.

I take it none of your horn wires go anywhere near the alternator?

Charge Light should only come on when ignition turned on, then go off as soon as you start engine.
Check battery leads are tight and no more than 1" movement on longest stretch of fan belt. You should have about 14.5 volts across battery with engine running if you can check that the battery is charging.
After that confirm alternator cables are on correctly. If you put a spanner on the terminals to tighten disconnect battery negative first.