Lift pump question

[LSstepside]

I have a question. I have a 1999 Chevrolet K3500 cab, and chassis. The lift pump is not transferring fuel. From what I've read here, the lift pump transfers fuel when it sees a 25% difference in ohms between the level transmitters. The rear reads from 0-90 ohms. The front reads 40-240 ohms empty to full. Do I have the wrong level transmitter in my main tank? I read an article here that said what wires do what, and tested everything, and the ohms in the main tank are the only thing that didn't make sense. I can't find a main fuel tank fuel housing assembly that reads 0-90 ohms. Everything is operating properly otherwise. If I ground out a certain wire, the lift pump kicks on like it's supposed to.