The battery could be getting weak but it's not the cause of the current problem. The generator keeps it charged up while driving and it supplies the current for the car's electrical system. The dim lights and slow windows were the clues that there was a problem. That gave you the warning time to get safely off the road.
If you charge the battery at a slow rate for an hour, you should be able to drive up to half an hour if you don't turn on the lights or heater fan. Have the charging system tested. Often the voltage regulator / brush assembly is all that fails, and used to be pretty easy to replace, but Ford has also had a design problem that makes replacement of the generator a better choice.
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Thursday, December 20th, 2012 AT 4:49 AM