Battery/alternator

[Ellie-shaye]

Hey everyone. Just after some information/help. My partner has a rear view mirror that’s a reversing camera in his ls400. However a few days ago this stopped working. Last night he changed the connectors etc, fixed the issue and within an hour the headlight levelling notification popped up, and so did the Battery light. We’ve tested the Battery and it’s still keeping power, however, if he takes his foot off the accelerator the Battery light comes back on, until he puts his foot down and it goes off again. 
we’ve had no issues with this car till this. Could it be the alternator, or has he tripped something due to adding a new connection for the camera? Is it a completely different issue before we fix the alternator? 
 

thankyou!! 

[ColinBarber]

Is the 12v Battery low on charge? Possibly due to interior lights/radio etc. being on whilst working on the vehicle. If the Battery charge is good then the best thing would be to disconnect the mirror to eliminate that as a source of the problem. If it's not that then possibly a fuse has blown or it's an unlucky coincidence.

[steve2006]

As above, nearly flattened the Battery leaving the doors open a few times.