Fuel Pump Relay

1990 Pontiac Grand Prix STE, 3.1 VSECTION Fuel Pump Relay
  1. Disconnect fuel pump relay. See SYSTEM & COMPONENT TESTING article. Apply battery voltage and ground to fuel pump relay winding terminals. To identify fuel pump relay terminals, see appropriate wiring diagram in WIRING DIAGRAMS.
  2. Using an ohmmeter, check continuity between fuel pump relay power and fuel pump relay drive terminals. Continuity should exist. If continuity does not exist, fuel pump relay is defective.
  3. To by-pass fuel pump relay on-vehicle (fuel pump not operating), turn ignition off. Disconnect fuel pump relay connector. Using a fused jumper wire, connect fuel pump test connector to positive side of battery. Fuel pump should run.
  4. If fuel pump runs, check for faulty connections to relay or replace defective relay. To locate fuel pump test connector, see the SYSTEM & COMPONENT TESTING article in this section.
Fig 1: Typical Fuel Pump Relay Schematic
G90D13212Courtesy of GENERAL MOTORS CORP.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.