DTC B1C43-23: Master Interior Light Switch - Signal stuck low: Action

WARNING: This page is about a different car, the 2018 Jaguar XF, 2017 Jaguar XF, and 2016 Jaguar XF. However, it is still accessible from the selected car via links, so may be relevant.

Refer to the relevant system wiring diagrams and check the interior lamp switch circuit for short circuit to ground
Check the operation of the interior lamp switch