Ok

The ohm reading across the plug [ unplugged from sensor] with key off should be around 1200-1300 ohms, regardless of temp...this value does not change to any degree with temp changes ..it is the sensor that changes w/temp. So, if you are getting different readings at that female plug [ you mention 300 to 1000 ], you have a problem in either the wires from the sensor plug to the N22 module or a bad N22 .
You mentioned that you had changed that plug ..WHY was that..did you have bad insulation at that harness?????
The x26 plug is around that fuse box somewhere and that is just a plug in the harness that is between the sensor and the module for firewall disconnect.
Your sensors values are Ok , but your N22 module is triggering early.
The sensor feed at N22 is pin #8...you should have perfect cont [ trace ohms]between that pin and one side of the sensor....

Here are some comparablereadings I just did on a working chassis ...[w/o a bridging resistor. [ie/stock wiring]

At 20C amibent :
Sensor 6.3K
Plug -1250

At 80C:
Sensor -625
Plug- 1250
This is using the temp gauge as temp reading source.

The default will not trigger until approx 80C. The fan will trigger below default by jumper at plug.