Electric window drivers side not working

If the switch on the passenger side works, it should not be the relay. These switches are usually the fault, and can be dissasembled carefully and contacts cleaned. Theyre not that expensive anyway if I remember last time.
Other things to consider are the wires coming into the drivers door. make sure that one of them is live, and if you ascertain which on is the live, which the ground/earth, and what is the window motor one, you should be able to test the wiring.