560sel warning light

[t300]

I just bought 1986 560 sel bronze w/brown interior 199,000 miles for $1000.00 at an auction but it seems in really great condition!
Being completely new to and amazed by this car , just a quick ? for now .
A warning light just lit .It is located in between the windshield wiper fluid and the antilock brake warning indicators.It looks like a circle with an exclamation mark in the middle.What is it? this a lame question ,which brings me to this question. could anyone suggest a good source for an owners manual and a service manual ? I have a set of mitchel on demand disks ,but its coverage of the 560 is pathetic!

thanks