How do you power it with a 12V battery

Hello 👋🏻 I did indeed, it’s been a new purchase and I got excited

My 56 plate Range Rover Vogue seems to be stuck in low range, the switch doesn't seem to be responding. Is there any way that I can by-pass the switch to get it back into high range? Annoying isn't the word, Christmas period = long delivery times for the part and garages shut