Most of the controls work via cable, but the far right fan control pushes open a flap in the heater box via a mechanical rod.




Maybe you could just leave the rod out? The heater would still have most of its function. Or another option would be to make a custom length rod. I've done this before by using something like an old coat hanger, it's about the same gauge as the stock rod.

Personally I'd go with rallycar's suggestion of in the glove box. Also easier to switch back if you change your mind in the future.