No, a seized rear wiper arm on a Ford Expedition would not directly drain the battery. The wiper motor is only activated when the wiper switch is turned on. A seized arm prevents the wiper from moving, but it doesn't create a continuous electrical draw. The motor might draw a small amount of current when initially activated and then stall, but this wouldn't be enough to significantly drain the battery over time.
However, if there's another underlying electrical problem, such as a short circuit in the wiper motor wiring, that *could* drain the battery, even with the wiper arm seized. The seized arm is simply a symptom, not the cause of battery drain in this scenario.
