If you probe one of the yellows, if it is not grounded, you will see +12v on it, flowing in from the red, through the coil and out the yellow looking for a ground.
The controller provides that ground, so the yellow will be at 0v, and then when it wants the coil to fire, opens the circuit, which causes a spark and the yellow rises back to +12v for the dwell time, and then it grounds again.
So you are saying the yellow is staying at +12v even while cranking?
It could be a sensor problem, not seeing engine rotation, or it could be a controller just not doing its job.