Fuel Pump Failure

What type aircraft?  If it’s an RV-12iS, has the Van’s HIC module SB been implemented?

Obviously you'll check the electrical side of things (CB, connections etc) but we had one that did this (on a new installation). We turned the pump on and gently tapped the body of the pump with a mallet and, hey presto, it came back to life. Presumably it's an impeller arrangement within the pump and the tapping was enough to free the temporarily stuck 'rotor'. No problems since.

Next event is to check the fuses in the big fuse box ?

An easy first test is to swap the connectors on the two pumps.  Then turn on the pump #2 switch and see if pump #1 runs.  If it does the problem is upstream of the pump, if not then it’s the pump. If it’s the pump then send the complete pump set to a certified Rotax repair station or replace the single pump if you are comfortable with that. 

If it’s not an RV12 with the HIC module, and the problem is that there is no power to pump #1, first check fuse F5 in the Rotax’s fusebox.  Also check the condition of the pin/socket #11 in the X1 connector at the bottom of the fusebox.  The (+) wire to pump #1 routes from fuse F5, through the X1 connector Pin 11, then directly to the pump.  The (-) wire side routes from the pump, through the fuel pump switch, then to the ground plate on voltage Regulator A, which is on the left side of the fusebox when facing it.  So, the (-) is the switched side of the circuit, and the positive lead will be energized anytime the start power or emergency power switch is closed, or anytime the engine is running.  

It's a Tecnam P2008

I will try swapping the connectors...