On my 2018 plus 4 the BCU controls the led footwell lights, with a timer. The BCU has four relays in it but I don’t know what they are.
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In the wiring loom under the tool tray there exists wiring for interior lights which I have used to fit an LED to the rear bulkhead. This simply works on / off with the door switches and seems to be Independant of the BCU

Last edited by Tim Crump; 08/10/21 05:53 PM.
Tim
Plus 4 2018