How can I make an effect that stops and starts sync with intensity

I would like to make an effect where a light moves along a path, for example. effect 903, figure 8.  I want the movement to stop when the light comes from 0 to FL intensity and then move while dark to the next position.  If I just combine the two effects, the light moves while it is fading up and down, but I want it to be stationary during the fade.  What is the best way to accomplish this?

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