2010 GMC Acadia Fuel Pump Relay Location: A Complete Guide to Finding and Fixing It

If you own a 2010 GMC Acadia and are experiencing starting problems, stalling, or a lack of power, the fuel pump relay is often the first component to check. The fuel pump relay on a 2010 GMC Acadia is located under the hood, mounted to the left of the radiator core support, inside the main engine compartment fuse box. This small black box with three or four electrical connectors controls the power flow to your fuel pump, and when it fails, your engine won't get the fuel it needs to run. The good news is that this relay is easy to access, test, and replace, often without any special tools.

Understanding the Fuel Pump Relay

The fuel pump relay acts as an electrically controlled switch that sends power from your battery to the fuel pump. When you turn the ignition key to the "on" position, your Engine Control Module (ECM) sends a signal to the relay, telling it to close the circuit and allow voltage to flow to the fuel pump. This pressurizes the fuel system so the engine can start. The relay only keeps the circuit closed while the engine is running or cranking, which is a safety feature that prevents the fuel pump from running if the engine stalls or the ignition is left on without the engine running.

Without a properly working relay, the fuel pump won't receive power, and no fuel will reach the engine. This is why a bad relay can cause your Acadia to crank but not start, or to stall unexpectedly while driving.

Symptoms of a Bad Fuel Pump Relay

A faulty fuel pump relay can cause several noticeable problems. If you notice any of these symptoms, the relay is a good place to start your diagnosis:

  • Engine cranks but won't start: This is the most common symptom. You can hear the starter motor turning the engine over, but the engine never fires up.
  • Stalling while driving: The engine may suddenly lose power and shut off, especially at low speeds or when idling.
  • No fuel pump noise: When you turn the key to the "on" position (before starting), you should hear a brief humming sound from the fuel pump in the rear of the vehicle. If you hear no sound, the relay may not be sending power.
  • Reduced engine power and poor acceleration: If the relay is intermittently failing, the fuel pump may not deliver consistent pressure, causing sluggish performance.
  • Decreased fuel economy: A failing relay can cause the engine to run lean (too little fuel), which reduces efficiency.

Step-by-Step Guide to Locating the Relay

Finding the fuel pump relay on your 2010 GMC Acadia is straightforward. Follow these steps:

1. Park safely and open the hood. Make sure the vehicle is off, the parking brake is engaged, and the engine is cool to the touch.

2. Locate the main fuse box. The underhood fuse block is located on the passenger side of the engine compartment, near the battery. It is a large black plastic box with a removable lid.

3. Open the fuse box lid. Look for the latch or clips holding the lid in place. Press or release them to lift the lid off. The underside of the lid usually has a diagram showing the location of each fuse and relay.

4. Identify the fuel pump relay. On the diagram, look for the label "FUEL PMP" or "FUEL PUMP" relay. In the 2010 Acadia, this relay is often designated as K46 in the fuse box layout. It is a standard-sized cube relay, typically black or gray in color, with four or five metal prongs underneath.

5. Confirm the location. If the diagram is unclear, compare the relay to known components. The fuel pump relay is usually located near other large relays like the horn relay or the cooling fan relay. You can also consult your owner's manual for a detailed diagram specific to your vehicle's trim level.

How to Test the Fuel Pump Relay

Before you buy a new relay, it's wise to test the existing one to confirm it's the problem. There are two simple methods you can use.

Method 1: Relay Swap Test

This is the easiest method and requires no special tools. You simply swap the fuel pump relay with a known good relay from another system in the same fuse box.

1. Find a relay of the same type. Look for a relay that controls a non-critical system, such as the horn relay, the HVAC fan relay, or the headlight relay. These are usually identical in size and pin configuration to the fuel pump relay.

2. Remove the fuel pump relay. Grasp the relay firmly and pull it straight up. You may need to rock it gently side to side to loosen it. Avoid using excessive force.

3. Remove the known good relay. Carefully pull out the relay you identified as a good substitute.

4. Swap the relays. Place the suspected bad fuel pump relay into the socket of the known good relay (e.g., the horn relay socket). Then place the known good relay into the K46 fuel pump relay socket.

5. Reconnect the battery and test. Reconnect the negative battery terminal. Attempt to start the engine. If the engine starts and runs now, your original fuel pump relay is bad.

6. Confirm the swap. Test the system you borrowed the relay from. For example, if you used the horn relay, honk the horn. If the horn no longer works (but the car starts), it confirms the original K46 relay was faulty.

Method 2: Using a Multimeter

If you have a digital multimeter, you can test the relay more precisely. This method requires a bit more technical knowledge but provides a definitive answer.

1. Disconnect the battery. Always disconnect the negative battery terminal before working with electrical components.

2. Remove the relay. Pull the K46 relay out of its socket.

3. Test the coil circuit. Set your multimeter to resistance (ohms, Ω). Touch the probes to pins 85 and 86 on the relay itself. You should see a resistance reading between 50Ω and 150Ω. If the reading is out of range (open circuit or short), the relay coil is bad.

4. Test the contact circuit. Set the multimeter to continuity (beep) or resistance. Touch the probes to pins 30 and 87 on the relay. With the relay at rest (no power applied), the meter should show no continuity (infinite resistance, no beep).

5. Apply power to the relay. Use small jumper wires to apply 12V battery power to pin 86 and ground to pin 85. When the relay clicks, the meter should now show continuity between pins 30 and 87. If it doesn't, the relay contacts are burned or stuck.

6. Test the socket for power. With the relay removed and the battery reconnected, turn the ignition key to the "on" position. Use the multimeter set to DC volts. Probe pin 30 of the socket: it should show battery voltage (around 12.6V). Probe pin 86: it should also show voltage when the key is on. If voltage is missing, the problem may be in the wiring or the ECM, not the relay itself.

Replacement Procedure

Once you confirm the fuel pump relay is faulty, replacement is simple.

1. Disconnect the battery negative terminal. This is a safety precaution to prevent accidental shorts.

2. Remove the old relay. Pull the faulty relay straight out of its socket. If it's stuck, use a pair of pliers gently, but be careful not to damage the socket.

3. Obtain the correct replacement part. The GM OEM part number for the fuel pump relay on a 2010 GMC Acadia is often 15307045, 15308857, or 13580715. You can also purchase a standard Bosch-style automotive cube relay that matches the original's physical size, pin layout, and amperage rating (usually 20-30 amps). Auto parts stores can cross-reference the exact part for your vehicle.

4. Install the new relay. Align the prongs of the new relay with the socket and press it firmly into place until it clicks. Make sure it is fully seated.

5. Reconnect the battery. Reattach the negative battery terminal.

6. Test the system. Turn the ignition key to the "on" position and listen for the fuel pump to prime (a brief humming sound). Then start the engine. It should start smoothly and idle steadily.

Why Choose KEMSO for Your Fuel Pump Replacement

If after testing the relay you find that the fuel pump itself is the problem, or if you simply want to upgrade to a more reliable component, KEMSO Racing offers high-performance fuel pump solutions for your 2010 GMC Acadia. Their fuel pumps are designed as OEM replacements, meaning they fit perfectly and meet or exceed the original manufacturer's specifications. Every KEMSO fuel pump comes with a lifetime warranty, giving you peace of mind that your investment is protected. Whether you need a direct replacement or a performance upgrade for better fuel delivery, KEMSO products are built to last. You can browse their full selection of fuel pumps and other automotive parts by visiting their website: https://www.kemsoracing.com/.

Final Tips for a Successful Repair

  • Always disconnect the battery before working on the fuse box or any electrical components in your Acadia.
  • Double-check the diagram on the fuse box lid. Some vehicles have slight variations in relay placement depending on the production date and optional equipment.
  • Keep the old relay as a reference when purchasing a new one. This ensures you get the exact same pin configuration and amperage rating.
  • Prime the fuel system after replacing the relay. Turn the ignition to the "on" position for 2 seconds, then off for 10 seconds. Repeat this cycle 5 to 6 times before attempting to start the engine. This helps re-pressurize the fuel lines.
  • Inspect the relay socket for corrosion, bent pins, or melted plastic before installing the new relay. If the socket is damaged, the new relay may not work reliably.

For more information on high-quality fuel pumps and automotive parts, visit KEMSO Racing at https://www.kemsoracing.com/ today.


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