Subject is my 1992 Dodge Caravan 3.3L A401 trans.

I just had the transmission totally rebuilt to the tune of 1400 bucks
about 6 months ago and it works better than new. Prior to the rebuild
I had the occasional issue with the park/neutral safety switch. A few
swings of the transmission from park to first solved it.

Last week in the morning no start. First move was to replace the
switch. To no avail... I traced down the wiring and all components
work.. Starter relay works fine out of the car. The relay has 12 volts
in and has trigger voltage from the start position of the ignition
switch. This means no ground. I check ground on the relay connector
and no there isn't one. Not in park not in neutral not in anywhere. I
pull the new switch. and check it.. there is continuity between pin 2
and the metal contact on the end of the sensor. (no continuity to the
case) The two outside pins (backup lamps) have continuity when the
metal contact is depressed. moving the nylon (1/2") plunger makes no
difference to anything.

My thoughts .. it is not making contact to ground inside the
transmission. I have tried reseating the sensor, 2 or three times.
How does it make contact and with what inside the transmission.

In the meantime I will try bypassing the switch from relay to ground.
Just to get it to the shop.

I bet this is another trip to the transmission shop.

I had one more try... and got it. So for reference to others, here
was the solution. I had my daughter run the transmission through park
to first several time so I could feel the pins go by with my pinky
finger. Yes they all seemed to make sense small one in park and
longer one in reverse and a small one in neutral then none in drive or
1st. several gaps between them all. I put the new switch back in and
lo and behold it started. Must have been crud on the sensor posts in
the trans and I cleaned it off on the end of my finger.

Cheers
Marv