2002 Audi A6 Quattro
 

Have 2002 A6 with no owner's manual. Can anyone tell me what sensor light depicts what looks like a beaker with water droplets. I have not experienced it but wife states she saw it. She says it was in red lighted area of speedometer. She couldn't take eyes off road because she was driving at the time. Is it a low coolant symbol? Wife states that it was not a low oil indicator light. I have to send away for an owner's manual.