Whenever the pump is silent when jumping the fuses, that's when you need your voltmeter. Intermittent functionality could mean power loss or pump malfunction. The voltmeter will tell you which it is. Preferably, keep the pump plugged in, and find a way to safely get the voltmeter leads on the plug leads on that black connector in the trunk without shorting anything, and then jump the fuses and see what the voltmeter says.
You gotta do this while you are experiencing the 'no response' scenario from the pump though, so maybe wire up the voltmeter, go for a drive, then as soon as you come back you're ready to test it out.
Jump fuse, silent pump, voltmeter reads ~12V, you've got a problem between the connector & pump.
Jump fuse, silent pump, voltmeter reads 0 or a few volts, now you know you need to snoop up the line and check grounds, spades, etc.
Did you make sure to replace/attach the ground ring terminal?