My Quest stopped running while driving one night. It will turn over but will not resart. I suspected a fuel pump failure because I don't hear that 5 to 7 second fuel pump "buz" that you get when you first turn the key. I made sure the fuses related to the pump are good. Since the pump is submerged in the tank and would cost me about 150 dollars, I applied 12 volts to the connector on the fuel pump wiring harness and heard the pump running. I got under the hood to the relay compartment and tried another "green" fuel pump relay but still no buz or starting. I removed the relay and with the key turned on, I get 12 volts on two of the four terminals. Jumping these termials together still doesn't run the pump. I'm thinking a detailed wiring diagram is what I need to troubleshoot this problem. Has anyone else experienced wiring problems associated with the fuel pump? Does anyone know where to get a good detailed wiring diagram/schematic? This van has served me well so if I can fix it myself for a reasonable amount of money I'll keep it.
Thank you for your time.

Check for a broken ground. The wiring diagram is in the haynes manual or you can look in on the mercury villager forum there is a guy who will scan that page or any page for you.