I was looking at a friends 3rd gen 4runner (i believe its a 99) and he has a digital thermostat. is there any way to upgrade to that from a manual one?
Not cheap and not easy.
The digital climate control is only in the Limiteds and you'd have to replace not only the whole control panel but also the electric motors that control the vents.
not to rub it in, but the climate control is awesome. i have it one my rig, and its the easiest thing to use ever. you dont have to deal with the hot or cold knob, you just turn the knob and set the degree that you want.
My mom has a '99 Limited and the digital setup is nice and includes outside temp but simple is good too since the manual version is pretty much trouble free.