my car cuts off when I wash it. I change the fuse and it starts right up.

Hello, There is a connector or module on that circuit that is getting wet and blowing the fuse. If replacing the fuse works every time, that is fantastic, but sooner or later (maybe now) corrosion will contribute to absolute failure of that circuit. Get the wiring diagram, follow the path of that circuit, and find where it is getting wet, is corroded, or is damaged by water. The other thing is that allowing some time to dry may bring it back this time too, but have the issue handled soon. Jaguars are already notorious for electrical issues.