2004 Chevrolet Silverado 3500HD - Help request - Fuel gauge issu

trying to diaganose inop. fuel guage on 2004 chev c5500 dual tanks

I would look at stepper motor.

First of all, make up your mind which vehicle you have

Is it a Silverado 3500HD . . . ?

Or is it a C5500 . . . ?!

They are completely different trucks

And I have to know what you’ve got before I give any advice

I suspect that C5500 isn’t a choice in the scroll down at the Car Complaints site. I would trust the OP’s statement over the title.

I’ll say one thing, in regards to the C5500 and stepper motors . . .

They don’t commonly have those problems, unlike the smaller GM trucks of the era

Very rare

We have plenty of GM trucks in our fleet, of various vintages, class 1 - 8 . . . and the class 4 and up trucks don’t really have the same problems as the smaller ones