When I was changing the driver side rear air spring I noticed a pipe that was just forward of the top the air spring. It was a black plastic coated metal pipe that looked like it was going towards the diesel tank. It literally fell off when I touched it (about 9 inches of it) and it had obviously been corroded right through for a long time. Does anyone know what it is? The only thing that doesn't work is the rear washers, is this it?