Testing The Fuel Pump Relay (1997-1999 Chevy/GMC Pick Up And Suburban)

TEST 4: Bench Testing The Fuel Pump Relay

Bench Testing The Fuel Pump Relay. How To Test The Fuel Pump Relay (1997 Chevy/GMC 1500 Pick Up)

Bench testing the fuel pump relay is pretty easy and in this test section I'll explain the test.

In a nutshell: We'll manually apply battery power and Ground to terminals 85 and 86 of the fuel pump relay with 2 separate jumper wires.

Then we'll check that continuity exists on terminals 30 and 87 (see illustration above) with your multimeter in Ohms mode.

The illustration above (which is a front view of the relay terminals) will help you with your multimeter and jumper wire connections.

These are the test steps:

  1. 1

    Connect terminal 85 of the relay to the battery's Ground (-) terminal using a jumper wire with alligator clips.

  2. 2

    Connect terminal 86 of the relay to the battery's positive (+) terminal using a jumper wire with alligator clips.

  3. 3

    With your multimeter in Ohms mode, probe terminals 30 and 87 (see illustration above).

  4. 4

    Your multimeter should show continuity with the relay powered up with the jumper wires.

    I don't have an Ohms value to give you, but your multimeter should read anything but the letters OL.

  5. 5

    Remove the jumper wires.

    Your multimeter should register no-continuity (with the letters OL) on relay terminals 30 and 87.

Let's analyze your fuel pump relay bench test results:

CASE 1: The multimeter showed continuity in the indicated terminals. This is the correct and expected test result and tells you that the relay is functioning correctly.

CASE 2: The multimeter DID NOT show continuity in the indicated terminals. This test result confirms that the relay is defective and needs to be replaced.

Fuel Pump Circuit Diagram

Fuel Pump Circuit Diagram. How To Test The Fuel Pump Relay (1997 Chevy/GMC 1500 Pick Up)

NOTE: The above fuel pump circuit diagram applies to the in-tank fuel pump of the 1997-1999 5.0L and 5.7L Chevy Pick Up and SUV.

More GM 4.3L, 5.0L, and 5.7L Tutorials

You can find a complete list of GM 4.3L, 5.0L, and 5.7L tutorials in this index:

Here's a small sample of the tutorials you'll find in the index:

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