Car died on me the other day just after leaving the in laws and refused to start although it coughed and spluttered a bit. Couldn't hear pump priming which seemed strange, after slamming the bonnet shut it fired up. New Fuel Pump fitted which then also refused to prime the fuel lines, much tracing of voltages showed no power getting to pump, managed to locate the pump relay and wiring (I'm going to ache tomorrow after contorting myself in the drivers footwell), shorted the pins which would usually switch the pump and everything sprang to life. Found that the switched 12V supply to the relay was good so relay became the main suspect. Connected relay direct to the battery and got it switching, must have been dirty relay contacts, all ok for now but going to replace it anyway.
Weather didn't help things yesterday
But the wax is doing its job