Other possibilities, though less likely, include:
* Faulty window switch: While the switch itself might be stuck, this is less probable if the problem is only happening with the rear window. A short or intermittent connection in the wiring leading *to* the switch is more likely.
* Wiring harness issue: Damage or short circuits in the wiring between the switch, the regulator, and the body control module could cause the window to roll down. This often manifests as intermittent behavior.
* Power issue: While less common, a fluctuation in power could cause the window motor to activate unexpectedly. However, this would likely affect other electrical components as well.
The window regulator is the most straightforward and common cause. The mechanism wears out over time and the internal components can get jammed, leading to erratic behavior. Replacing the regulator is typically the solution.
