5.9 Magnum help needed

If you have spark, most likely fuel.
Sometimes the sock on the end of the pump will clog up.
If you hear the pump running you can put a small amount of air pressure like 15 psi with the gas cap off, and blow the sock off the end. Did this on my uncles 96 years ago and it is still running.
If it ends up being the pump it is easier to pull the bed loose and slide it back than dropping the tank.