yes fastpakr it does change, from ambient outside (67 when I tried it) to about 100F and if you are in the middle then it is about partway between them, so, yes, it changes. I should be getting hotter air than that, I'm running 190-195F thermostat. It should be hot as heck. Still suspect mix door, if not that, heater core. Haven't had a chance to do anything more with it, I'm thinking, flush the heater core well in both directions then try it again and see if it makes any difference at all. That's non-invasive. If it doesn't make any change at all, then, either the heater core was ok to begin with (or totally fubar, but I doubt that since both hoses get hot, so water is going through it), and it's back to the blender door stuck, broken, or the drive to it messed up somehow. I'm pretty sure the actuator is doing its thing.
I actually have a couple of those ratcheting screwdrivers, in regular and phillips. Also a bit driver. They're sometimes indispensable.