I bought 95 b3500 used, it hsa a bad fuel pump and I replaced it 18 months ago.
The fuse now blows but is not consistent. Some times is blows on cranking and others in a 1/2 hour so. Seeing how it will run, to me means the fuel pump is good. I suspect a bare wire, but have no idea where to start. I do have a service light on for the radiator fan system.
Any ideas?

 

No it doesn't. If the fuel pump has an issue that is loading down the circuit to the maximum, the fuse could take time to blow. The ambient temperature around the fuse will also be a factor.

 

Thank You for the response. How then should I test the fuel pump, and what would cause it to malfunction?

 

Pull the fuel pump fuse and connect an amp meter across the fuse terminals, then start the engine to see what the pump is drawing for amps.