Hello, Advice needed in California

I'm a new member and need some advice. I have a 6 yr old Chihuahua. She sleeps in a crate during the night and is usually out all day. But she pees in the crate during the day and at night sometime. The crate in next to the back door where she would go outside. The door to the yard and the crate are both open all day and she will go outside sometimes. But for no reason will go pee in the crate instead. She loves her crate and will go in there to sleep even during the day. So I just don't know why she would urinate in there. Any advice on how to stop this would be helpful. Thank you