Inertia switches are a F*rd thing.
Anyhow - check the power wire all the way to the back. If you've got power on the (pink? damn - not looking a dwg) wire at the back, then check the ground. Does your fuel gauge read right? They share a ground.
I've had a case where the fuel pump power wire was actually broken INSIDE the insulation! Took me forever to track that one down, since everything LOOKED like it was OK. Kept probing the wire every foot or so with a fine pin. Eventually the power disappeared, and I just worked my way back. Good tug on the wire, and it snapped in two.