2002 Mercury Marquis engine won't crank

Ok lets not over think this ok. You do have nuetral safety switch or it would start in any gear not just park or nuetral. You mentioned that the alternator and the battery was replaced, but has anyone checked the starter or starter solenoid on the starter? I suspect that the starter or solenoid on it is the problem. If you would like to check something when it does it again put it in nuetral and see if starts. Otherwise I would have the starter checked. Get back to me with what you find out. Thanks and have a great day.

Your SITE keeps throwing me off before my answer is completed. This has happened TWICE now. I will go offline and answer in MS Word and paste my response back here. You really need to find out what kicks me off the " Your Message" section before I'm anywhere near done!

Reply to racefab966: I thought your first reply was very vague and generic and it appeared that you might not have access to Ford/Mercury information. For example per FMC the Grand Marquis (GM) DOES NOT have a Neutral Safety Switch, per se! It does have a Transmission Range Sensor mounted on the transmission with does a similar function however FMC indicates that it rarely fails. Also, neither the FMC nor I feel we should jump right to replacing the starter with its built-in solenoid. If you had access to Ford/Mercury Technical Support Bulletins or TS Memorandums you would have noticed two related ones. One FMC TSB (6-19-14 Oct 06) discusses starting system; no crank condition. It describes no crank condition due to open circuit condition in the starter relay to starter motor circuit at the starter motor connection. This IS THE AREA where I already stated I cleaned & WD40 lubed all three solenoid connections. Apparently the FMC can replace the circular spade lug with another type but this should not be the solution since everything appears (low impedance) at that point on the solenoid. The second FMC TSB is 01-21-13 Oct 01 and it discusses HIGH EFFORT to rotate key cylinder from RUN to START position apparently due to defective chime switch that is mounted on the side of the key cylinder. This might make it difficult for an older women with weak wrists to rotate the key cylinder that last hard 10 degree’s to activate the start switch which then sends power to the starter/solenoid circuit.
FYI; my VIN is 2MEFM74WX2X659390) in case you can pull up specific auto related FMC files.
So far you haven’t provided any useful information that wasn’t already considered. I was hoping for info similar to the above which I provided to you OR other info from your experience and/or GM database.

At the moment IF/WHEN it happens again I plan on having my wife:
1. Try to change her hand position on ignition switch to exert more rotational torque on the key switch. (Could show if chime switch causing need for excessive force to turn ignition switch to the START position, and
2. After key is in RUN position put foot on brake and shift into NEUTRAL position to try to start it from that position (could show misalignment of Transmission Range Sensor).

Please let me know IF YOU CAN ADD ANY INFO OTHER THAN WHAT I HAVE PROVIDED ABOVE AND IN ORIGINAL PROBLEM STATEMENT.

Forgot to indicate that there are NO ERROR Codes as measured by a AutoZone person with diagnostic reader.

Ok first off I have done this for more then 20 yrs and am certified. I do have access to all the info that I may need and sometimes to much. Now first off I would check the starter to make sure that it is getting power to the solinoid when you put the key in the start possition. Here is a pic of the neutral safety switch it is on the trans were the shift cable hookes up at.

The range sensor is on the left side of the transmission other wise known as neutral safety switch. Now if you raise the car to get to it you must turn off the air suspension if so equiped. There is a term on the starter solenoid labeled "S" in the start possition you should get power there is you do then you need to make a jumper to go from the "B"(batt.) term to the "S" term and see if the starter turns over if it doesn't then replace the starter if it does get back to me and we will go from there.