Speed Sensor (for cruise control) LOCATION on speedometer?

[JohnFitzpatrick]

I want to locate and test the Speed Sensor for the Cruise Control on an '84 300SD. I read that the speed sensor is "either on or in the speedometer, or inline with the speedometer cable." Specifically on an '84 300SD, where is the Speed Sensor, relative to the speedometer, and what does the Speed Sensor look like? Thanks.

[rdsw]

My cruise control doesn't work, so I'd like to know too....