The heater blower motor typically only works on high. Occasionally it will turn on if on 3rd setting (4th is high). I'm guessing that the problem of earlier Taurus models where water gets into the motor is still an issue, but so far am not able to confirm that.
Blower only works on high on 2008 Ford Taurus
by gjlindn in Highland, WI on January 12, 2011
ANSWER by DaveJHM on January 12, 2011
Sounds like a typical failure of the blower motor resistor.
blower only works on high
It started last month. High is the only position on the dial that works.
The cabin filter was changed a month ago at 40,000 miles. The switch barely works on any setting except high and then it blasts you. This happens on all settings: ac, heater, defrost and vent.
I just changed my battery because it died.