2003 Mercedes Benz CLK430 No power to fuel pump

If I understand you correctly " Fuel pump is getting power to it when the key is out & the car is off"

(sorry I clicked the wrong button) If I understand you correctly " Fuel pump is getting power to it when the key is out & the car is off" this would mean that the battery on your cars is going dead is that correct? When you first turn the key on the fuel pump will come on for 5 seconds to prime the system then they will be no power at the fuel pump, when you start to crank the vehicle the fuel pump will come back on. You will need a friend to help you one to crank over the vehicle and the other one to check the fuel pump to see if it has power.