2000 Mustang GT fuel pump issues Please help!

Fuel Inertia Switch!

1sickstang said:

It ran fine and then nothing. I have changed everything people have told me that can go out. Does the fuel cut off switch have power to it?

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Yes, with your ignition switch on, you should have voltage at both ends of the inertia switch for 2 to 3 seconds. That is if the switch is working properly. The red button on the inertia switch should be pressed down, and should stay down. When it is down, voltage should flow through the switch then to the fuel pump. If your engine is not starting, (like in your case) you will only see voltage for 2 or 3 seconds. So, have someone turn your ignition switch to the on position while you test for voltage at the inertia switch. Test both sides of the inertia switch. If you don't have voltage at either end of the inertia switch with your ignition switch on for 2 to 3 seconds, that would indicate problems with your CCRM. The CCRM is a multiple relay module which supports various circuits, the fuel pump is one of those circuits. If you do have voltage at both sides of the inertia switch, then test the wire connector at the rear of the gas tank, just above the bumper. Disconnect the wire connector and test the side that runs to the inertia switch. If you have voltage there with the ignition switch on for 2 to 3 seconds, that would then indicate that your fuel pump went bad. I'm thinking you are testing for voltage by yourself, and by the time you get to the inertia switch, the 2 to 3 seconds has passed by and that's why you don't see any voltage at the inertia switch. Let us know how things turn out. Hope this helps, Tommy.

Fuel inertia switch has no voltage?

1sickstang said:

The fuel cutoff is not getting power at all not even for a few seconds.

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Have you found your problem yet? If you don't have power at your inertia switch, then you have to back track to your Constant Control Relay Module. On some years, it is located under one of the front seats. On other years it is located under the passenger side front fender. Between the front fender and fender well, just forward of the strut tower foundation. The CCRM is a multi function relay which supports I believe 3 circuits. Your ac, your fan, and your fuel pump. There should be 3 relays installed inside the module. You need to find out which one supports your fuel pump and test for voltage. I believe to get at the module, the fender has to be removed. I can look for an electrical diagram if you want to do you own troubleshooting. Have you checked out and tested any of the fuses for the fuel system? Let me know, Tommy.

2000 GT Mustang Fuel Pump Wiring Diagram

Here is a wiring diagram for a 2000 GT Mustang fuel pump circuit, which is posted in 3 sections. That's the only way I could post it. This should be of help to you as it shows you how the circuit is being supplied with power and where the wires are running to. I high-lited some of the wires just to make it easier for you to trace. The colors I used have no bearing on the actual colors of the wiring. The actual color of the wires are clearly marked for you to see. Please note where your fuses are and their sizes. These fuses must be checked and tested with a tester. A visual test is not good enough to determine if the fuses are good or not. In the last diagram, the Brown/Pink wire is the hot wire, and the Red/Black wire is the ground wire. These two wires are the wires that run directly to your fuel pump. So, if you are not getting voltage at your inertia switch, you need to trace back to your Constant Control Relay Module. Check to see if you are getting voltage coming out from the Pink/Black wire of the Constant Control Relay Module. Your Fuel Pump Relay located inside your Constant Control Relay Module may have gone bad. Hope this helps. Good luck, Tommy.