29* C is about 84* F....and while that's a good temperature for the warm area of a corn snake's enclosure, what is the cool side being kept at?
My corn snakes all seem to prefer around 70-73* & they use the UTH area on & off when digesting their meals, but not constantly.
When you say "warm side", that suggests that you might (?) be heating too much of her cage. How much of her cage is heated? (what proportion?)
Corn snakes require (& prefer) far less heat than BPs, & while it's normal to talk about warm & cool 'sides' of the cage for a BP, I'm concerned that you may
be over-doing the warmth for your corn snake, & that's why she is clinging to the coolest area she can get.
If your ambient ROOM temperature is 70* (or low 70's*), as mine is most of the year, the heat area provided for your corn snake should not be larger than roughly
a sixth of the cage. (it can even be less!) Even a fourth is too much, & you may be over-heating her, unintentionally of course.
So again, what is the cool "side" temperature? and how MUCH of her cage is at which temperatures? Also, what size & kind of cage is she in? The smaller
the enclosure, the easier it is to over-heat your snake. I've kept corn snakes for many years (& bred some too)...I prefer & recommend glass tanks with
plenty of air-flow thru screen tops. My adults are in 40 gal. 'breeder' tanks with controlled UTH under one corner. When my house gets warmer in summer
(up to 80* before A/C kicks on) I turn their UTH's OFF until room temps. again go back down.
Keep in mind that we are 98.6* roughly, so yes, your corn snake will ALWAYS feel cold to you...if she ever feels warm she'll be overheated & probably dying.