84 k30 fuel gauge not reading correctly

[J.Peart]

The fuel gauge in my 84 k30 diesel just started reading a full tank as a bit above 1/4 full on the gauge. Seems to work otherwise. Gauge harness seems to be plugged in fine. Is this a sending unit or gauge issue?

 

[THEFERMANATOR]

Most likely it's a sending unit problem. Check the resistance with an ohm meter, should be 0 ohms empty, and 90-95 full.

 

[Husker6.5]

So, get your gauge problem figured out, @J.Peart ?