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Home >> GMC >> 1998 >> C3500 HD 7.4 J, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing 7.4L >> Fuel System >> Fuel Delivery >> Fuel Pump Oil Pressure Switch (Back-Up Circuit)
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Fuel Pump Oil Pressure Switch (Back-Up Circuit)

To test fuel pump oil pressure switch (fuel pump back-up circuit), start engine. With engine running, disconnect fuel pump relay. If engine stalls, fuel pump oil pressure switch is faulty. If vehicle continues to run, switch is okay.