1997 S10 Fuel Pump Relay: The Complete Guide to Location, Diagnosis, and Replacement

The bottom line: The fuel pump relay on a 1997 Chevrolet S10 is located behind the glove box, inside a dedicated relay center, regardless of whether you have the 2.2L four-cylinder or the 4.3L V6 engine. This small but critical component controls power delivery to the fuel pump, and when it fails, your truck will crank but won't start. Understanding exactly where it is and how to test it can save you hours of frustration and hundreds of dollars in unnecessary repairs.

Why Your Fuel Pump Relay Matters

The fuel pump relay acts as an electromagnetic switch that allows a low-current signal from your truck's Powertrain Control Module (PCM) to control a high-current circuit that powers the fuel pump. Without a working relay, the fuel pump won't receive power, and your engine won't get fuel.

When you turn the ignition key to the "ON" position, the PCM sends a two-second prime signal to the relay. This signal energizes the relay's internal coil, which closes the circuit and sends battery voltage to the fuel pump. You should hear a distinct "click" from the relay and a brief whir from the fuel pump in the tank. If you don't hear either, the relay is a prime suspect.

The fuel pump relay is also part of a redundant safety system. The oil pressure sending unit can provide backup power to the fuel pump once oil pressure exceeds 4 PSI, which is why some trucks will run even with a faulty relay—as long as they start first.

Fuel Pump Relay Location: Behind the Glove Box

The exact location of the 1997 S10 fuel pump relay is behind the glove box, on the passenger side of the dashboard.

Here's how to access it:

Step 1: Empty the glove box completely. Remove all papers, manuals, and junk.

Step 2: Look at the back wall of the glove box opening. You'll see a small access door or panel, often marked "Relays" or "Relay Center."

Step 3: Open this access door. You'll see a small relay center with several relays mounted inside.

Step 4: The fuel pump relay is typically the first relay from the left.

Step 5: If you're not sure which relay it is, look for the one with a stamp or part number that matches the diagram in your owner's manual. The relay itself is about 1.25 inches square and is usually black.

Important note: Some online sources and older forum posts may suggest a different location, such as under the hood in the fuse block. For the 1997 model year, the factory service information confirms the relay is behind the glove box. The engine compartment fuse box may contain other relays (like the A/C compressor relay or the blower motor relay), but the fuel pump relay is not there.

Engine-Specific Information

The fuel pump relay location is the same for both engine options available in the 1997 S10:

  • 2.2L L4 (VIN 4): The fuel pump relay is behind the glove box, on the relay center.
  • 4.3L V6 (VIN W, X): The fuel pump relay is also behind the glove box, on the relay center.

How to Test the Fuel Pump Relay

Before you buy a replacement relay, you can test the existing one. Here's a straightforward approach:

Method 1: The Listen Test

Turn the ignition key to the "ON" position (don't start the engine). Listen carefully near the glove box area. You should hear a single, distinct "click" from the relay. This click indicates the relay coil is energizing. If you hear the click, the relay is likely working, and the problem may be elsewhere. If you don't hear a click, the relay or its control circuit is suspect.

Method 2: The Swap Test

Find another relay in the same relay center that is identical to the fuel pump relay. Common relays that often share the same part number include the horn relay. Swap the suspected fuel pump relay with the horn relay. If the fuel pump starts working (you hear it prime) and the horn stops working, the original relay is bad.

Method 3: Multimeter Test

If you have a multimeter, you can test the relay directly:

  1. Remove the relay from the relay center.
  2. Identify the terminals. The relay has four or five pins, typically numbered 30, 85, 86, and 87.
  3. Terminal 30 should have constant battery voltage with the key off. Test with a multimeter.
  4. Terminal 85 should receive 12 volts from the PCM when the key is turned to "ON" (for about two seconds).
  5. Terminal 86 is connected to a permanent ground.
  6. Terminal 87 is the output that sends power to the fuel pump.

If you have voltage on terminal 30, ground on terminal 86, and a signal on terminal 85 when the key is turned on, but no voltage on terminal 87, the relay is bad.

Common Symptoms of a Bad Fuel Pump Relay

Engine cranks but won't start: This is the most common symptom. The starter motor turns the engine over, but the fuel pump doesn't run, so no fuel reaches the injectors.

No fuel pump priming sound: When you turn the key to "ON," you should hear the fuel pump run for about two seconds. If you don't hear it, the relay or the pump is not getting power.

Intermittent stalling: A failing relay may work sometimes and not others, causing the engine to stall unexpectedly while driving.

Check engine light: The PCM may set a diagnostic trouble code related to the fuel pump circuit if the relay is intermittent or failed.

No click from the relay: When you turn the key to "ON," you should hear the relay click. If you don't, the relay coil or its control circuit has failed.

Troubleshooting Beyond the Relay

If you've tested the relay and it's good, but the fuel pump still isn't running, check these components:

Fuel Pump Fuse (20A): Located in the under-hood convenience center. This fuse protects the high-amperage side of the fuel pump circuit. If this fuse is blown, the pump won't get power regardless of the relay.

Fuel Pump: The pump itself is inside the fuel tank. To test it, you can check for voltage at the fuel pump connector, which is located on the frame rail just behind the fuel tank. Probe the gray wire with a test light or multimeter while an assistant turns the key to "ON." If you have voltage and ground at the connector, but the pump doesn't run, the pump is bad.

Wiring and Grounds: Check the wiring harness along the frame rail for corrosion or damage. The gray wire between the relay and the fuel pump is a common failure point on S10s, especially in areas with road salt or high humidity. Voltage drop in this wire can cause the pump to run weakly or not at all.

PCM Signal: If the relay isn't getting the trigger signal (dark green/white wire) from the PCM when the key is turned to "ON," the PCM itself may be faulty, or there may be a problem with the ignition switch or theft deterrent system.

Fuel Pressure Specifications

If you suspect the fuel pump itself, checking fuel pressure is the next logical step. For a 1997 S10 with the Vortec engine, the correct fuel pressure with the key on and engine off is 60-66 PSI. If pressure is low (below 55 PSI), the fuel pump is likely worn out. If pressure is zero, the pump is either not getting power or has failed completely.

Replacing the Fuel Pump Relay

Replacing the relay is a simple job that takes about five minutes:

  1. Remove the relay access door behind the glove box.
  2. Pull the old relay straight out of its socket. It may require a firm tug.
  3. Push the new relay firmly into the same socket.
  4. Test by turning the key to "ON" and listening for the click and pump prime.

The OEM part number for the fuel pump relay is 13502676, and it's also used for the horn relay and several other applications.

When to Call a Professional

If you've tested the relay, checked the fuse, verified power at the fuel pump connector, and still can't get the pump to run, the problem may be deeper in the electrical system. A qualified mechanic can use a wiring diagram to trace the circuit and identify issues like a bad PCM, a broken wire in the harness, or a faulty ignition switch.

Recommended Fuel Pump: KEMSO Performance Fuel Pump

If your testing confirms that the fuel pump itself has failed, you need a reliable replacement. We recommend the KEMSO brand Fuel Pump for your 1997 S10.

KEMSO fuel pumps are high-performance, OEM replacement units designed to meet or exceed the original factory specifications. Each pump is built with precision components to ensure consistent fuel pressure and long service life. Whether you have the 2.2L four-cylinder or the 4.3L V6, KEMSO has a direct-fit solution that installs easily and performs reliably.

Why choose KEMSO?

  • High Performance: Engineered to deliver the correct fuel pressure (60-66 PSI) that your 1997 S10 Vortec engine requires.
  • OEM Replacement: Direct bolt-in fitment. No modifications, no adapters, no hassle.
  • Lifetime Warranty: KEMSO stands behind every product with a lifetime warranty. If your fuel pump ever fails, KEMSO replaces it—period. That's the kind of confidence you want when you're dropping the fuel tank or removing the truck bed.

Visit KEMSO's website to find the exact fuel pump for your 1997 S10: https://www.kemsoracing.com/

KEMSO's commitment to quality and customer satisfaction makes them the go-to choice for DIYers and professional mechanics alike. Don't settle for a cheap pump that might fail in a year. Invest in a KEMSO fuel pump and get back on the road with confidence.

Summary: The 1997 S10 fuel pump relay is located behind the glove box. It's a common failure point that can prevent your truck from starting. Testing it takes just a few minutes with a multimeter or by swapping it with another relay. If the relay is good but the pump isn't working, check the 20-amp fuse, the wiring to the tank, and the fuel pump itself. When you need a replacement fuel pump, choose KEMSO for reliable performance and a lifetime warranty. Visit https://www.kemsoracing.com/ for more information.


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