You don't check it at the relay. You can do that for testing the actual relay (outside car with 12v source). But right now we want to test if the pins themselves are getting any voltage. You check it at the female terminals that the pins to the coil of the relay go to. Only thing you can do at the coil with the relay out the car, for what we are checking for, is to check for resistance (I suggest you do this anyways). And unless you know exact OHM specs, you will be limited. If it has resistance, it works. If it doesn't, then it doesn't. But a bad coil isn't necessarily an on/off thing (though really is). It could be something like the coil not creating a large enough magnetic field to close the relay. That is why specs are important.

You set your meter to DC voltage. With engine off, place the prongs into the 2 female terminals that the coil of the relay would go. First just go to the start position to see if there is any life (if the pump would have primed, it would have shown voltage on your meter). But since the pump does not prime each time you place it in the starting position, you would need to crank the engine to see if there is life (will show voltage reading, then zero, voltage reading, then zero repeatedly rather fast). I'm sure there is a better method, but what I would have done. Actually, I would have just swapped in a spare used OEM from ebay but you get the point. Also unplug your injectors during this to not have them spray fuel and flood your chambers.

If somebody has a better method, please post. Pretty sure my method won't make his meter too happy.