1) Disconnect the body integrated unit connector (i84).
2) Measure the resistance between the body integrated unit and power window switch.
Connector & terminal
(D102) No. 2 — (i84) No. 15: (D102) No. 1 — (i84) No. 29:
Is the resistance less than 10 Ω?
Replace the body integrated unit.
Repair or replace the harness.