[AzTumbleweed]

I can't say about Escorts but it used to mean that your alternator was bad if a car did this. It should run without the battery and the alternator provides electricity. But I really don't know nowadays. If you haven't been having any trouble then I'd say leave it alone.

Turn on your ignition and disconnect the temperature sending unit. Check the gage. Then ground out the wire that goes to the sending unit and look at gage. On one of these the gage will peg out and the other it won't move (forgot which). If it doesn't then the gage is bad. If it does then the sender may be bad.