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There are only a handful of components involved in the operation of the window. Primarily the regulator, switch, relays (located on and controlled by the immobilizer) and the wiring between these things.

Since you've replaced the regulator and swapped switches, that leaves the immobilizer and wiring.
As Thom said, check your wiring before committing to an expensive immobilizer fix. It would be worth while to look at and possibly clean the door harness connector (inside the door jamb) and the immobilizer harness connector.

If the immobilizer shows signs of water damage, you could try a gentle cleaning with isopropyl alcohol and a soft brush, but once they have visible corrosion, they usually require professional repair.

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