The two middle lights in my digital fuel gauge are lighting up properly.
How do you test it to determine if it's the sending unit or the digital read out in my fuel gauge?
Is there a way to test the individual led lights in the fuel gauge?

 

Tough one ain't it?

 

Simplest way to test it would be to provide a varying DC voltage to it covering the range the sending unit does. Not enough information to say just what that is, though.

You could try combinations of 1.5V batteries. Just keep adding another in series and touch the leads (make sure you've got the polarity correct). Once you've gotten to 8 batteries you'd have 12V. At varying points the different LEDs should light. An eight-pack of AAs ought to tell you what you need to know, and you can always use them in your TV remote later.

 

Good tip...I think it is the sending unit because the two middle ligths were not working properly on the previous LED Gas Gauge either.

 

Here's the specs on the sending unit. If you check it with an ohm meter while filling the tank you will see if it is at fault.