Chrysler Repair: 99 300M starter replacement/starter circuit short, jumper wires, extension cables

Question
QUESTION: My daughter's '99 300M had been getting hard to start--would have to cycle the key numerous times to get the starter to engage.  I had a new battery installed (normally would do it myself but they only charged $16 and since it is in a less than ideal location I paid to have it installed) but later that day I ended up having to jack the car up so that I could tap on the solenoid to get the car started so I decided to get the starter rebuilt.  As you know, the starter isn't all that easy to get at but after removing the motor mount and oil filter I got the starter out.  My local rebuild shop went through the solenoid and starter (contacts were bad) and starter checked out fine on the bench.  I reinstalled the starter and hooked up the negative batter cable.  Everything seemed to power up OK and was normal until I moved the key to the start position at which point everything went dead (oil pressure lamp was the only thing that would illuminate on the dash).  I'm not sure if the solenoid engaged or not but I do know that the car didn't crank over at all.  After disconnecting the starter electrically I did get the dash and courtesy lights to power up again.  Pulled the starter out again and had the starter rechecked and it worked fine (although without any load on it--but amp draw looked good and starter sounded good).  Reinstalled the starter and the exact same thing happened again.  Next I'm going to try hooking the starter up to car with some extension cables and jumper wires but with the starter not mounted to the engine to see what happens.  Do you suspect that I've got a bad ignition wire to the solenoid?

ANSWER: Hi Vern,
You can check out the system without removing the starter. The low current wire from the starter relay to the starter motor is light green. You could jump from the fat red wire that comes direct from the battery to that connection of the light green wire on the solenoid and that should produce a normal cranking of the motor. If not then there is something wrong with the starter motor or the solenoid. Be careful doing that jump because you have a direct connection to the battery and so you would not want to accidentally ground the jumper which would cause a huge current and burn your hand.
If that shows to be OK, then the issue would be either the starter relay in the power distribution box under the hood or the light green wire from it's pin D to th solenoid. If you remove the relay, the rear two pin sockets are the ones that the relay connects: the rear most has battery supply up to 40 amp from fuse G, and the next to rear pin is the one that has the light green wire connected to it.
You could verify that the light green wire is not grounded along its path by measuring the resistance of that pin to ground with the relay removed and the wire disconnected at the starter solenoid. If that is not grounded, then you should be able to jump from the rear pin of the socket to the next to rear pin (mimicking the relay's action) and the starter motor should fire up. If it does, then I would suspect the starter relay is shorted to ground when the points close or there is a short to ground in the wire from the start position of the ignition switch (yellow) to the "joint connector" in the pdc, or from that connector's pin 4 to pin A of the relay socket, or from  pin C of the relay socker to pin 31 of the pcm, or from pin 5 of the connector to pin 8 of the tcm (all are yellow wires). A and C are the outside and inside pins of the 3 socket pins of the relay that are side by side by side, where outside means nearest the edge of the PDC. I hope this is clear.
That yellow wire is also supplied by fuse G, but via the start position of the ignition switch.
So check those all out and see what you find.
Roland

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QUESTION: Just one clarification--when you refer to the pin socket locations after removing the relay, I'm not sure what you mean by the rear position.  I need to know your frame of reference--do you mean toward the rear of the car or to the rear (passenger side) when standing alongside the drivers fender adjacent to the power distribution box.  Right now I can't get more than about 5 volts across the jump start connections if I hook up the negative cable.  I get 12.7 on the battery cables until I hook up the negative to the engine ground cable so it would seem that something is shorted continuously now.

Answer
Hi Vern,
Thanks for asking that, I hadn't taken into account the positioning of the box, just how it was shown on the page, without reference.  By "back" I meant the outboard narrow end of the box, and the 'side by side by side' are the three, arranged front to rear of the car, where C is the front-of-the-car-most, and A is the rear-most, nearest to the rear long edge of the boz. I don't understand which battery you are speaking of in the jump situation. What is the voltage on the 300 battery with the clamps off, and with the clamps on?  Maybe the battery is just defective or grossly discharged. See what the ohm reading is between the two disconnected clamps.
Roland