Serious problem? - chrysler 2001 van

I finally got my mitts on my van to see what is up with the erratic
shifting/transmission issue the girlfriend was talking about. It is
rather hard to describe, but here is an attempt.

All the indicator lights (PRN3DL) come on when it is started.
Sometimes when I shift gears, it will move to define the R or D or N,
etc. Other times all the lights will come on so you do not know where
the shift position actually is. The shift itself and the transmission
seem to go into position properly, it is the indicator that is messed
up. Sometimes you know it is in D, but L will come on. Sometimes the
van will not move as a result. Othertimes you can move through the
gears and it will display properly. It is intermittent in nature, but
is becoming quite frequent now.

Once it is gear and moving, it all seems to work exactly as it should
from the perspective of the automatic shifting, etc under all
different loads, speeds, and acceleration.

Is there some sort of switch on the shift mechanism going?
Transmission solenoid? Bad computer ground? Something really
disasterous?

It has about 93K on it and the transmission oil was changed at about
45K.

Any ideas on what to check?

Thanks and regards. A bit of a novice on the newer vehicles, so please
be gentle. lol.