Q: Fuel system, inertia relay, or pump will not start, never had problems in the past

Hello there, thank you for asking about your 2007 Ford Explorer. The first thing to do is to have the fuel pressure tested to see if the engine has pressure. Make sure the Theft Light is not on or flashing. This theft system will disable the pump. Then have the computer scanned to check for codes and diagnose them as needed. If there are no codes or the Theft Light is off and there are no problems with fuel pressure, then check for power to pump by accessing the inertia switch in the right inside the passenger kick panel. Remove the panel and make sure the inertia switch is not tripped. Check the wiring for power to fuel pump when the key is turned to start or cycling on and off. If you have power then your fuel pump is not working and needs to be replaced. Try hitting the bottom of the fuel tank while someone is cranking the engine. If the vehicle now starts then the pump should be replaced and the tank cleaned out if debris and metal particles are seen in the bottom of the tank. If you would like help doing this, a certified technician from YourMechanic can inspect your starting problem and replace the fuel pump if necessary.