2009 6cyl ford escape battery light on power steering stops momentarly as well as heater controles not working tach stops batt and alt check out fine

 

The individual parts like alt and battery can check out fine, but if that power can't get to the rest of the vehicle there is a problem.

A good place to start checking is the connections where the battery is connected to the vehicle. Keep in mind the can look good, but still have corrosion under them.
The right way to clean them is to remove them , clean them, then reinstall them. Looking at them does nothing !

If that doesn't help, we need to check for power and grounds to parts of the vehicle. A 2009 vehicle has had 13 years to permit corrosion to make a home.