633 speed control

I just purchased a 1981 633CSi and the speed control does not function. You push the lever forward and remove your foot from the accellerator pedal and the vehicle will accellerate but will not lock into speed. You release the lever and car slows down. Any suggestions. There doesn't seem to be any workshop manuals available at least at the BMW dealer for 6 series.

the 1981 is based on the e12 so the Guys over at firstfives.org may be the best source of information.

http://firstfives.org

Later,