Combines Mice in top of cab

try moth balls or ex-laxx

Your problem is a hole somewhere, but aside from that, mice are alergic to mothballs

look for holes where they can get in.Sometimes gromlets or seals around wire harnesses or cables can be dislogded.Maybe boots around pedals.If they can't get in you have no problems.

The mice that get up in the combines in our shop use to get up the cab posts and then into the head liner fixed them with a can of expandable foam . never a mouse in the cab again.