Hello and welcome to Just Answer. My name is Denny; now let me see if I can help you with your question.
Replace the crank sensor. " no crank signal reference" means the PCM does not see a crank signal.. Chrysler's are know for bad crank sensors, and this would be the first thing I would do.
You don't have to yell. You asked where the signal source was, like you were going to trace wires.
The crank sensor is bolted to the transmission bellhousing near the motor. As far as what it looks like; buy a new one, then you will have it in your hand to compare to other sensors. ( there should be only one in the tranny bellhousing) .