as i recall the wire connection is above the left drivers knee in the nest of wires.

it is much easier to simply check continuity between the relevant wires at the L bracket with the same color wire at the abs computer front of the passenger seat under the front carpet.

i think arts right about the location of the problem. the only other thing might be a damaged window pane signal ring inside the differential.

only non filthy way to check it is jack up the rear end so axle spins by rotating the tires and remove speed sensor. have someone slowly rotate the tire, trans in neutral while using a strong light to inspect the slowly turning speed tone ring.

or remove pumpkin cover and look closely.