I just drove 50-70 miles on my front tank and it is still on full. My rear tank is showing below the where it was when I switched to the front. So I am thinking that even though the guage is showing the front tank it is actually pulling fuel from the rear tank.

My question is is there a sure fire way of telling which tank the fuel is being pulled from? I did just have both tanks off the truck so I wonder what might have caued this to happen...

Thanks
Thad

 

Pull a tank sender wire off a tank see if it still shows a level...... If the valve is selected to a specific tank the last thing switching is the fuel level sender......

 

So, you are saying that if the gauge is showing a different reading that I am getting fuel from the proper tank?
If so, it just caught me as odd to go that far and see no change from the full position.

 

I drove around for another twenty minutes with a spare fuel can just incase I was wrong....I was. The switch and everything is working properly, I am just ADD.....