Chrysler Repair: Park/Neutral switch: 07 Pacifica

Question
I have 2007 Chrysler Pacifica. Sometimes will. Not start. Turn the key, everything comes on except the car. No clicking just dead. Turn the key to acc, move the shifter from park to neutral let car move just a bit. But sometimes not moving. Put shifter back in park, the car starts right up. Was doing this once every other week. Now becoming more frequent. Once a week. I think it's the neutral switch, but not sure. What do you think?

Answer
Hi David,
It sounds like that could be it. The P/N switch is located inside the transmission on the internal switch that senses where the gear shifter is positioned. The cable from the shifter lever to the transmission may be slightly out of adjustment or the electrical contact inside the transmission could be flaky.
First check whether the starter motor relay in main power box makes a soft click when it won't start. If that is the case, then either the 12v from the ignition switch is not getting to pin 85 of the relay socket, the powertrain control module is not 'seeing' the grounding of the park/neutral switch on its pin 27 of the black/green 4th multi-pin plug at that module which otherwise would cause the pcm to ground pin 86 of the relay which would cause the relay to click, or the relay is flaky.
So take a look at the pin 85 of the relay socket (that is the front pin) to see the voltage on that pin when you try to start it (after removing the relay from the socket) and similarly see what the resistance reading to ground is on pin 86 (that is the rear pin of the socket) before you try the starter and then what is the resistance to ground when you try the starter (again do this with the starter relay removed from its socket). If you are not getting the readings:
Then try moving the shift lever slightly off center of the P or N detent to see if that corrects the situation. If so, then adjust the shift lever cable at the transmission's vertical rod by putting the shifter in Park, then loosen the adjusting screw for the cable at the shift lever, then pull the shift lever all the way forward and retighten the adjusting screw to 6 foot pounds of torque.
Let me know what you observe.
Roland