Megane II Lights Dimming Q

[Waugh-terfall]

Noticed the other day, and earlier that when locking my car whilst the See-Me-Home Lights are on, the tail lamps dim with the indicators. I.e. When the indicators are on, the red lamps dim, then brighten up again when the indicators are off. I don't know if it does it whilst driving i.e. tail/brake lamps flash when I indicate, shall look into that tomorrow. Any idea as to what it could be? Could the battery (1yr old) be weak?

Thanks

[Mr Jenks]

Got a poor connection to the lamps or a bad earth

[StoatInACoat]

Earth problem on the rear cluster. Could be due to water ingress.