2000 Blazer Fuel Pump Fuse: Complete Guide to Location, Diagnosis, and Replacement

The bottom line: If your 2000 Chevy Blazer won't start or stalls while driving, the fuel pump fuse is one of the first things you should check. The fuel pump on a 2000 Blazer with the 4.3L Vortec engine does not have its own dedicated fuse labeled "fuel pump." Instead, the pump gets power through the ECM B fuse (a 20-amp mini fuse) located in the underhood fuse block on the driver's side of the engine compartment. Blown fuses are common, but often the real problem is a faulty fuel pump relay, a bad ground connection, or a failing fuel pump itself. Knowing how to find and test these components can save you time and money before you drop the fuel tank to replace the pump.

Where Is the 2000 Blazer Fuel Pump Fuse Located?

The 2000 Chevrolet Blazer fuel pump fuse is not labeled as "fuel pump" in the fuse box. It is the ECM B fuse, a 20-amp mini fuse. You will find it in the underhood fuse block, which is located on the driver's side of the engine compartment near the battery. The fuse block has a black plastic cover that snaps off, and there is a diagram on the underside of the cover showing fuse positions .

The ECM B fuse supplies constant battery voltage to terminal 30 of the fuel pump relay and to the oil pressure switch. If this fuse blows, the fuel pump loses power completely, and the engine will not start .

Additionally, the fuel pump circuit also relies on the ENG I fuse (10-amp), which provides switched ignition voltage to the control side of the fuel pump relay. If this fuse is blown, the relay will not energize, and the pump will not run .

According to the 2000 Chevrolet Blazer owner's manual fuse box diagram, the fuse that controls the fuel pump circuit is listed as:

  • Fuse position 24 (or 43 depending on diagram version): 20-amp mini fuse labeled "Engine Control Module, Fuel Pump Module, Oil Pressure"

How the Fuel Pump Circuit Works on a 2000 Chevy Blazer

Understanding the power flow helps you diagnose problems faster. Here is how the system works step by step:

  1. Constant power flows from the battery to the 20-amp ECM B fuse in the underhood fuse block. This supplies power to terminal 30 of the fuel pump relay and to the oil pressure switch .

  2. When you turn the ignition key to the "ON" position, the 10-amp ENG I fuse provides power to terminal 86 of the fuel pump relay.

  3. The Powertrain Control Module (PCM) then grounds terminal 85 of the relay for exactly two seconds to prime the fuel system. This closes the relay, connecting terminal 30 to terminal 87, sending power to the fuel pump .

  4. If the engine starts, the oil pressure switch provides a backup power path. Once oil pressure exceeds 4 PSI, the switch closes and routes power directly to the fuel pump, keeping it running even if the relay fails .

Common Symptoms of a Blown Fuel Pump Fuse

If the ECM B fuse blows, your Blazer will show these symptoms:

  • Engine cranks but won't start – This is the most common sign. The starter turns the engine over, but you get no fire because the fuel pump is not pressurizing the system .
  • No fuel pump prime noise – When you turn the key to "ON," you should hear a brief humming sound from the rear of the vehicle (the fuel pump priming). If you don't hear it, check the fuse first.
  • Engine stalls while driving – If the fuse blows intermittently, the engine may die suddenly, especially under load or on rough roads.
  • Check Engine Light comes on – The PCM may log a code related to fuel pump circuit or low fuel pressure.

How to Test the Fuel Pump Fuse and Relay

Before replacing the fuse, follow these steps to diagnose the problem:

1. Locate and Inspect the ECM B Fuse

Open the underhood fuse box. Find the 20-amp ECM B fuse. Pull it out using the plastic fuse puller stored in the fuse box. Hold it up to the light. If the metal strip inside is broken, the fuse is blown. Replace it with a new 20-amp mini fuse. If it blows again immediately, you have a short in the wiring or a failing fuel pump that is drawing too much current .

2. Check the Fuel Pump Relay

The fuel pump relay is located right next to the ECM B fuse in the underhood fuse block. It is typically labeled as "F/PUMP" or "FUEL PUMP" on the relay cover diagram . To test it:

  • Swap the fuel pump relay with an identical relay from another circuit (like the horn or A/C relay). If the fuel pump starts working, the original relay was bad.
  • Or, use a multimeter to check for continuity across the relay terminals when power is applied.

3. Listen for the Pump

After replacing a blown fuse or relay, turn the key to "ON" (do not crank). Listen near the rear of the vehicle. You should hear the fuel pump run for about 2 seconds. If you hear it, the electrical circuit is working, and the problem may be the pump itself (clogged, worn out, or failing under pressure).

4. Check the Ground Connection

A poor ground at location G401 (on the rear chassis frame rail) can mimic a blown fuse or a dead pump. Corrosion or loose bolts here cause high resistance, reducing voltage to the pump. Clean the ground connection with a wire brush and tighten the bolt .

What Causes the Fuel Pump Fuse to Blow?

If you replace the fuse only to have it blow again, the problem is not the fuse itself. Common causes include:

  • A failing fuel pump motor – As the pump wears out, the internal motor bearings can seize or the windings can short, drawing excessive current. This blows the 20-amp fuse.
  • A shorted wire in the fuel pump harness – The wiring harness runs along the frame rail and can rub through, causing a direct short to ground. This is especially common on older vehicles with rust or damage.
  • A faulty fuel pump relay – A relay that sticks closed or has internal shorting can cause continuous power draw and blow the fuse.
  • Corroded connections – Moisture and salt can corrode the fuse terminals or relay pins, causing intermittent shorts.

Step-by-Step: How to Replace the Fuel Pump on a 2000 Chevy Blazer

If the fuse and relay check out, and the pump still does not run, the fuel pump itself needs replacement. Replacing the fuel pump on a 2000 Blazer requires dropping the fuel tank. Here is a basic overview:

  1. Relieve fuel system pressure – Remove the fuel pump fuse or relay, then start the engine and let it idle until it stalls. This depressurizes the system.
  2. Disconnect the negative battery cable – Always do this before working on any fuel system component.
  3. Drain the fuel tank – Siphon or pump out as much fuel as possible to reduce weight.
  4. Support and lower the fuel tank – Use a floor jack with a block of wood under the tank. Disconnect the filler neck, vent hoses, and electrical connectors. Remove the tank straps and lower the tank.
  5. Remove the fuel pump module – The pump is mounted on top of the tank. Turn the locking ring counterclockwise, lift out the module, and disconnect the old pump.
  6. Install the new pump – Transfer the fuel level sender and any necessary parts to the new pump module. Install the new pump, secure the locking ring, and reconnect all lines and connectors.
  7. Reinstall the tank – Raise the tank back into position, reconnect the straps, hoses, and electrical connectors.
  8. Test the system – Reconnect the battery, turn the key to "ON," and listen for the pump prime. Check for leaks before starting the engine.

Why You Should Replace Your Fuel Pump with a KEMSO Brand Fuel Pump

When it comes time to replace the fuel pump in your 2000 Chevy Blazer, you want a part that is reliable, affordable, and backed by a strong warranty. That is exactly what KEMSO Racing offers. KEMSO fuel pumps are designed as high-performance OEM replacement units that meet or exceed factory specifications. Whether you are driving a daily driver or a weekend warrior, KEMSO pumps deliver consistent fuel flow and pressure.

Here is why KEMSO is the right choice for your Blazer:

  1. Lifetime Warranty – Every KEMSO fuel pump comes with a lifetime warranty. If the pump fails for any reason, KEMSO replaces it. That is peace of mind you will not get from many big-box store brands .
  2. Affordable Pricing – Most KEMSO fuel pumps are priced at just $79.98, which is significantly lower than comparable pumps at AutoZone or the dealership. For a 2000 Blazer, that is a fraction of the cost of an OEM replacement .
  3. High Performance – KEMSO pumps are built with durable aluminum and stainless steel bodies. They support up to 600 BHP in naturally aspirated, turbocharged, and supercharged applications. The bypass valve is set at 125.8 psi, providing superior fuel regulation .
  4. USA-Based Support – KEMSO support is provided by USA-based technicians who know the products and can help you with installation and troubleshooting .
  5. Wide Vehicle Coverage – KEMSO offers fuel pumps for cars, motorcycles, ATVs, UTVs, and powersports vehicles. They have a growing catalog that covers popular models like the Chevrolet Blazer, Subaru Impreza, Honda Civic, and many more .

To browse the full selection of KEMSO fuel pumps and find the right fit for your 2000 Chevy Blazer, visit https://www.kemsoracing.com/. Their simple online store makes it easy to search by vehicle make, model, and year. You can also read their blog for detailed guides on fuel pump replacement and troubleshooting.

Final Thoughts

A blown fuel pump fuse on your 2000 Chevy Blazer is often a simple fix, but it can also be a sign of a deeper problem. Start by checking the ECM B fuse and the fuel pump relay in the underhood fuse box. If those are good, listen for the pump prime and test the ground connection. If the pump itself is dead, replacing it with a quality part like a KEMSO fuel pump is the smartest move. With a lifetime warranty and a price that won't break the bank, KEMSO gives you the reliability you need to keep your Blazer on the road.

For more information and to order your replacement fuel pump, go to https://www.kemsoracing.com/ today.


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