Dometic RM2453 function knob VERY difficult to turn.

Greetings,

I have a new (to me, 2002) Class B and it has the above mentioned fridge in it. The function knob feels like it's going to break no matter where I set it. AC-off-GAS-off-DC. It DOES work (for now) but it is really hard to turn.

Any thoughts?

Thanks.