Yesterday I filled up and flipped over to my front tank and took a road trip pulling a 14 foot enclosed trailer . When I got to my destination(hour drive) I noticed that the gauge had not moved! I flipped the tank gauge and my back tank showed a 2/3 tank. I'm guessing that its a stuck solenoid on the fuel selector so is there a good way to unstuck it. If it is broken is it interchangeable with gas units. Educate me please, Thanks.