Heating w/ Bigger Snakes?

-Pretty common sense I guess but I wanted other opinions on the matter. I have a 5ft Desert Kingsnake. I've given her the choice on hides and her heat. If I have her heat pad under a hide, she wont use it. If I have the heat pad under the center, she uses the hide. If I use the heat lamp, shes stays in the hide until night. If she soaks its at night, after the suns gone down. When I pic her up in the morning her body is cold but she doesn't use the heating elements I've provided. So ultimately. Should I try a different heat source or eliminate then all together?maybe your basking spot is too hot try sticking a heat mat to side of the tank