Double check and tighten all the connections on the alternator. Check and clean both battery post connections. Check and clean the fusebox connection under the hood (right behind the battery). Test drive your car.
If the above didn't solve the problem, have your alternator tested (especially Capacity test and the Diode test!). While you are there, have the battery tested.
Hope this helps! Radioman
Bad battery cable connection or dead battery
Pull off the battery cables and replace
Voltage regulator is defective. Have it replaced or this will ruin your battery.
Check the volts right from the battery, might be a faulty alt.
Open the hood and look see.
Dead battery Loose or corroded battery terminal Blown fusable link
There are several reasons why a Crown Victoria will not start. One reason could be a dead battery. Another reason is that the spark plugs and plug wires may need to be changed.
Mine on my 2003 is under the hood in a panel out near the battery.
take off the ground from the battery then put it back
Could be on the inner fender - follow the + battery cable
Disconnect battery for 15 - 20 mintues
most likely bad switch