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The letter next to each connector…140,402, 412 denotes the pin location…C,G, and A !!…what was disturbed in the back of the car during the header install ??
Ouch !!…85 is control side ground…J11 in wiring diagram…the test light should light on J12 going to the pump because you will find a ground through the fuel pump windings to ground so the test light should light…I think 30 is load side feed so see if you have power there with key ON…if so try jumping 87 and 30…if pump doesn’t run we will have to look at the connectors in the back…C402…since you have an 04 you have the FFS fuel system…fuel pump is on the top of the drivers side fuel tank…earlier C5’s at the bottom which are easier to access…another thing you can do is connect test light to ground and probe terminal 86 while you turn the key on…light will come on for 2 seconds and go out…this is fuel pump relay control…G401 (pictured) is a ground on the left frame rail inside the rear left tire…check that also !!
Found it I think. Had no ground at the pump connector so I tested continuity on the ground wire behind the rear wheel to the frame and had little to none. Took the wire off, cleaned and re-installed and now I have ground and the pump comes on when the key is turned on. Weird but it was apparently a completely separate issue from the headers. Thanks for the help, it got me where I needed to be and now I understand the fuel system better.
Great that you found the issue !!…let us know it’s a good fix….continuity/resistance checks on grounds isn’t the best method…you should check the ground with a test light or headlight bulb depending on how much current that circuit draws…with a fuel pump around 5 amps…if you hook up one lead of bulb to power and connect other wire to the ground circuit you are checking the bulb will be bright if it can carry that current back to the battery.
