what voltage should be at inertia switch on a E 150 van
you should have 12v at the swtich.
kbro is right, it should be the same voltage in as out of the switch. Check the supply side of the inertia switch, it should be battery voltage, then check the load side, voltage should be the same. The inertia switches do fail and won't deliver full voltage to the fuel pump. Also make sure that the connector is in good condition as they have been known to go bad also.
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