cantonine.......You need to stick some VERY bright lights under the dash when its dark. Go out to the firewall and see if there is any light. If so, use some spray foam and once its dry (next day), spray over it with rubberized undercoating available at your local auto parts store.
Also make sure that you're not getting any air leakage from around the doghouse cover. It could be blowing out the front of the cover and up under the dash. Generally this would be warm air, but in the winter, it could feel cold.
If all that doesn't work, buy her a blanket and a ski mask!