Engine Cooling problem
1996 Buick Regal 6 cyl Front Wheel Drive Automatic 140000 miles
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On the way home from work yesterday, the low coolant light started flashing. The car did not run hot at all. I stopped to check and sure enough, the coolant was low. Got some coolant, poured in more than enough (Filled up to hot level) and drove home. Low Coolant Warning light kept flashing. Checked at home and coolant level was still high.

This morning I checked the coolant level before starting the car and it was still the same. Started car. Low coolant warning light started blinking. Drove to work. Car runs fine. Never ran hot. After lunch I checked the coolant level, under the car for puddles (none) and started her up. No white smoke out of tail pipe. Low coolant warning light still flashing although coolant isn't low. Decided to disconnect negative battery cable to reset low coolant warning light (hopefully). Hooked it back up in two minutes. Not only did the car not lose my programmed radio station while the battery was disconnected (and I know that no power was running through car because I tried keyless entry and trunk release and they didn't respond) the low coolant warning light did not reset, which I think is a bit odd, unless this car has some sort of battery backup that I'm not aware of. How do I reset the low coolant warning light? Is this something that Autozone can scan for with an OBDII scanner and reset it?