Flashing LED

Out of the blue, Our 93 Park Ave, The service the engine soon indicator and a flashing red LED buy the temp Gage has occurred.
I am curious if anybody has experienced this before or possibly what might be the problem :screwy:
Any replies would be appreciated.

The small light tells you that your engine coolant has overheated, or your radiator cooling fans are not working. What was the engine temp gage reading when this occurred? What is the DTC number?

Never shown a overheat condition on the needle gage, The wife noticed it driving home from work on Friday, so she added coolant into the reservoir ( it was very low ) still had flashing led, so today I put a new thermostat in it and bled the air out of the system, Got the LED to quit flashing but I still have a service engine soon light, NOTE: cooling fans are working.
I disconnected the battery for 5 minutes still have service engine soon light :screwy:
I don't have an analyzer to get any codes, I will take into mechanic to get code if necessary.
Just curious if you know another way to reset code?

You don't need a code reader on this particular year, just follow the procedure shown HERE. (http://www.automotiveforums.com/vbulletin/showthread.php?t=679458)