i tryed whole day to set this heavy light, for camera mooving along the path, but always when in finish all is again caotic and wrong?!

i have one light @ the side of the camera like by a car this is 1.8 and when i follow the path always its to bright or to dark.
so i set -0.1 lights and +0.1 and for a time i set it it was right, but in the end everythig is to dark, i get crazy of this.
all lights are directional.

there is posted image to understand my mistakes... i dont know what to do because im loosing so many time.