My guess now is that my “bad part” seems to have the wire coil of Pin 8 broken, this is called the “2/4 Solenoid

My DTC was P0755 “Solenoid B”

P0750 is Solenoid A

Page 325 of the
2005 T&C van Transmission Diagnostic Procedures Manual
has the connector Pin Outs for the connector of the Transmission Solenoid/Pressure Switch assembly,
or TS/PSA for short

Page 326 is the schematic of all wires to/from Powertrain Control Module to connectors

For the connectors to the TS/PSA

Pin 4 is the common ground

Pins 5, 6, 7, 8 are wires leading to coils of solenoids where the coil completes a circuit to Pin 4 (Ground)

Pins 5. 6. 7 do show continuity across those coils to Pin 4 (Ground) so I guess those wires still good

Pin 8 is labelled 2/4 Solenoid Control

On my “bad” part:
Pin 8 DOES NOT show continuity to Pin 4 ( Ground) so perhaps a wire is broke/burnt in two

Pins
1. 2/4 Pressure switch Sense
2. L/R Pressure Switch Sense
3 OD/ Pressure Switch Sense
are switches shown in schematic on page 326 as normally open.

None show continuity to ground at Pin 4, as you would expect if those switch are normally open