Humming/Buzzing Noise While OFF. Toyota Rav4.
I have 2006 Toyota Rav4, 4 Cyl, 4WD, Limited with only 57,200 miles. For the past couple months, I have experienced issues with a humming/buzzing noise (similar to the sound of the old GM seatbelt signal, but at a much lower volume) coming from the engine (don’t know exactly where), but the engine is OFF, with NO key in the ignition. The problem is intermittent which makes diagnosing difficult. Sometimes the check engine, oil pressure and battery lights all are on BEFORE putting the key in the ignition. Other times, once I put the key in the ignition, then all of the noted lights illuminate. This issue causes the battery to drain to the point of not being able to start the car. I’ve replaced the battery, the entire auxiliary port, water pump and brake light switch. I have taken my car to several mechanics, including a Toyota dealership who forwarded this information along with videos (that I have) to the engineers at Toyota. So far, no one has been able to diagnose. Please help! I need reliable transportation.