service light on, gm cars, wiper blade

I don't have an owners manual for my 01 cavalier but a light goes on and off on my dash and it looks like a square with a water line with an arrow pointing down.  I know it means some level is low, but what fluid level is low?  Thanks.

Answer
    I don't have a Cavalier here to look at, but it's one of two things.  It's either the coolant or the washer solvent.  I think it's the washer solvent and that "arrow" is a pictographic representation of a wiper blade.  Either way, just look and see, both reservoirs are transparent and you can see the level right through them.  On GM cars the sender for the light is frequently bad.  This means that the level can be fine and the light will still come on.  New senders have to be obtained from a dealer.  Check the wire going to the sender before spending money on a new one, though.
Car Repair Talk's forum.