Hi. I recently developed an interesting issue in my 06 Taurus. With the AC running (manual control) when driving up-hill, the blower fan stops pushing air out of the vents. There is still noise being made, but no air-flow. I have tried messing with the speed and air-flow direction knobs while it's out but it doesn't have any effect on bringing it back (so I can probably rule out the speed resistor I replaced last year). After being back on level ground for a few seconds the air flow comes back and works as normal. What could possibly be causing this? Could the blower fan motor being going bad? Thanks for any input.