Wheel Speed Sensor
 

Maybe I'm not looking at the obvious, but.... I pulled off the right front wheel of my 1992 500SL to remove and clean the wheel speed sensor and I can't find anything that might be it. What does it look like and where is it? The posts I've read say it's on the wheel, but I doubt they really mean the wheel, maybe the rotor? Behind the rotor?
Or, maybe the wheel, I checked that, too. I'm not about to take apart anything before I'm sure it's the right thing.
Please give me some direction. :confused:

Here is a picture:

No wonder I couldn't find it. Thank you, the picture is very helpful.