Fuel pump voltage

i have a 1974 merz 450 sl which the fuel pump went out i replace it with a new one but now i dont get any current to the pump. i replace the fuel pump relay but still no power to the pump all fuses are good. but i heard that the merz is ground sentitive what ever that mean. help i got to get this thing running before it rust to death. thank you

You need to check for voltage using a test light probe at the places you mentioned.