When I was warming my truck up today in the parking lot, I noticed that when I switched from the rear to the front tank, an electronic whining sound occurs, (similar to a muffled smoke detector sound). When I first turn the key, but not enough to start the truck, the sound happens for about one second and goes away. The sound doesn't go away when the truck is running.

Does anyone know what this is? If so, what to do about it?

Thanks!

 

If you have the model which has a separate pump in each tank, the pump in the front tank is likely worn out more than the rear. SOME noise from the front, louder than the rear, is common, as most everyone uses the front tank almost exclusively, thereby wearing out the front pump first. If the noise goes away when switched to the rear tank, problem confirmed. The darling thing here is, you can use that front pump until it quits altogether, without becoming stranded in the boonies! imp