That tells us one thing: The Fan Module is powering up,but is not getting anything from the ECU.
This IMPLIES the ECU is not powered up. You previously said a code reader can't talk to the ECU - more evidence the ECU is not powering up.

FRom my study of the manual, the ECU is powered by two wires from the RCM. There are other 12 volt feeds, but the ECU is not powered by them, the ECU only sinks current thru those other leads to activate injectors, plugs or to read sensors. Connector C5 pins 3 and 9 of the ECU are what powers the ECU.

What I would do is verify the ECU has power and to do that, check for power at: ECU Connnector C5 pins 3 (always hot battery voltage) and 9 (12 volts when key is on).
These feeds come from the RCM. Perhaps you damaged the connector at the RCM or the connector at the ECU.

Red arrows show where battery voltage should be present at ALL TIMES. Green arrows show where 12 volts should be when the key is ON. We know the RCM is OK but is it possible a wire pulled loose in the connector at the RCM? Or maybe at the ECU? THis has happened before and you cant SEE it because it happens in the shell of the connector. Based on the fact the RCM and ECU have both been eliminated as causes, I think it may be something this simple.