Wring diagram here: GM UPFITTER - Body Builder Manuals

 

Thank you.

 

I am having the same problem did you ever figure it out?

 

That fuse is to cover tank-to-tank transfers for diesel trucks, as far as I know. Do you have dual factory fuel tanks?

 

No it’s a crew cab short bed. It says fuel pump fuse. And it has no voltage to it. Also nothing to relay

 

I'm pretty sure that the answer is that GM makes parts common to multiple vehicles and the fuse box is one of them. Not every fuse is used in every truck that receives this fuse box. The gas engine models appear to have a fuel pump control and a fuel pump. The electrical manual - GM UPFITTER - Body Builder Manuals - does show a pin on the ECM having an output to the fuse and relay on circuit 465 for fuel pump relay control, but no mention of circuit 465 anywhere else. However, it shows this location on the truck also - see attachment. When you look there near the fuel tank, don't be too surprised not to find a fuel pump. I don't think LMM's as a series have fuel pumps other than the one in the engine compartment, or if you have dual tanks, a transfer pump. I note that GM calls the device in the fuel tank that houses the fuel pickup and fuel sender a 'fuel pump' which confuses many/most people.

I suspect that if you test the ECM at pin 12 on the X-2 connector, you will find no output.

I have may have misinterpreted what I have read and concluded, perhaps you will find a different answer. Please let us know. Always willing to learn something new