Can you hear the pump running? If you let the fluid run dry ti will lose its prime and will not reprime unless you disconnect the
check valve first.
Not sure if the colors are the same on the newer kits, but, for my kit the blue wire from the controller goes to the pump +12V. I can unplug the controller and apply power to the blue wire from the battery and force the pump to run. I do this when I need to reprime or when I'm flow testing a new size nozzle.
You might try this just to see if it's the controller or the pump.