Mercedes 560SL R107 M117 Duty Cycle

[@nehuge]

MIne shows 99% solid and doesn't fluctuate while the car is running. What is going on? I have red probe in port 3 and black probe in port 2 on 1986 M117 560SEL engine and meter is set to "HZ%"

[@ionutboruga6015]

Thank you

[@ionutboruga6015]

In which hole number did you put the probes?

[@debauk18]

3 and 2 of the diagnostic socket X11

[@ionutboruga6015]

3 for duty cicle and 2 for ground
Thank you