1988 190E Warning Light
 

I just picked up a 1988 190E with 97K from the original owner. Well maintained with some minor issues I'll get after once the service manual I've ordered arrives. The car is lacking the owner's manual so I'm hoping someone can tell me what the thirdlight from the left (the round graphic between the battery and the brake) in the left side warning light cluster is. This is my first MB; my background is vintage aircooled VW's so the warning lights are all new to m e. Thanks.