Q: when i start my 2001 jeep Cherokee up, there is an electronic humming sound

Hello, thank you for writing in. Walking through the diagnostic process, we can rule out the wheels and suspension as a cause for the humming, as it happens as long as the car is running. The next step is attempting to replicate or control the noise through various tests, while keeping in mind we are trying to locate it. Listen for the noise with the vehicle in the "On" position to see if it is a radio circuit or speaker related problem, and to limit the amount of engine noise interfering with locating it. If messing with the radio and speaker controls has no effect on the noise, check the electronics below the driver’s controls on the dash board. There are several modules, solenoids, and other electrical devises located next to where your knees would sit while driving. For more help tracing down and resolving the noise, contact our service department to schedule an appointment.