I have a 2003 5.9L engine. The return port on sending/lift plastic cracked pumping fuel out and I replaced unit with a Airmax ? It looked the spitten image of o/e one that I took out. I didn't disconnect battery or fuse. I couldn't find a fuse that just indicated fuel sending or lift pump.

I put <> 15 gallons of fuel in and waited till lift pump stopped before I cranked engine to start it. Fuel gauge pegged at full. Then I filled with remain fuel that was 3-4 gallon from being full again pegged at full.. I then drove around neighborhood, after about a mile I heard a beep, lo fuel light came on and gauge reads empty now.

During the reassembly I sprayed the male and female pins with elec contact cleaner as fuel was all over things from the cracked return port. The cable connector that connects to sending/lift was hard to see the method of releasing and I broke the "locking tab" so there is no assurance I have a good mateing connection. As I write this I thought about that, but 2 pins do the gauge and other pins do lift pump is my assumption?? If it wasn't a good connection would lift pump work? Any ideas to try??