My 2007 Acura RDX's radiator fan stays on and keeps running until my battery is drained. I replaced the radiator fan switch sensor at the bottom of the radiator, replaced the coolant, burped the system, checked the relays and fuses, but I can't figure out why the fan keeps staying on. The Engine Coolant Temperature (ECT) sensor is in good working order. Anyone had a similar problem and solved it?