2009 GMC Acadia Fuel Pump Relay Location: A Complete Owner's Guide

The bottom line up front: On a 2009 GMC Acadia, the fuel pump relay is located in the underhood fuse block (also called the underhood fuse box), which sits in the engine compartment on the passenger's side of the vehicle . This is the same box that houses many other important fuses and relays for your Acadia's electrical system. If your Acadia cranks but won't start, or if it stalls unexpectedly, checking this relay and its associated fuse should be one of the first things you do.

This guide walks you through everything you need to know: where to find the relay, how to identify it, how to test it, and what to do if it fails. We will keep the language simple and practical, so you can get back on the road without unnecessary jargon.

Understanding the Fuel Pump Relay and Why It Matters

Before you start opening fuse boxes, it helps to know what you are looking for and why it matters.

The fuel pump relay acts as an electrical switch. When you turn the key to the "On" position, the engine control unit (ECU) sends a small signal to the relay, which then closes and allows a much larger current to flow to the fuel pump . This design keeps high-current wiring away from the dashboard and ignition switch, which is safer and more reliable.

The relay works together with a fuse. The fuse is a safety device—a weak link in the circuit designed to blow if the fuel pump draws too much current due to a short circuit or a failing pump . When the fuse blows, it cuts power to the pump and prevents damage to the wiring or even a fire.

On the 2009 Acadia, the fuel system is a returnless on-demand design . This means the fuel pressure regulator is part of the fuel sender assembly, and there is no return pipe from the engine. An electric turbine-style fuel pump attaches to the fuel sender assembly inside the fuel tank . When the ignition is turned on, the control module enables the fuel pump relay; if the module does not detect ignition reference pulses within two seconds, it disables the relay . This is normal behavior and something to keep in mind when diagnosing.

Where Exactly Is the Underhood Fuse Block on a 2009 Acadia?

The underhood fuse block is located in the engine compartment, on the passenger side of the vehicle . To access it, open the hood and look toward the passenger side, near the firewall or along the fender. It is typically a black plastic box with a removable cover . Lift the cover to access the fuse and relay block .

Many owners find it helpful to know that there is also a second fuse panel inside the cabin. The instrument panel fuse block is located under the instrument panel on the passenger side of the vehicle . However, the fuel pump relay is not in that interior panel on the 2009 Acadia—it lives under the hood.

Identifying the Fuel Pump Relay and Fuse in the Underhood Block

Once you have the cover off the underhood fuse block, look at the diagram printed on the underside of the cover. This diagram is your best friend. It shows the layout and labels each fuse and relay slot .

For the 2009 Acadia, the underhood fuse block contains a large number of fuses and relays. The relevant ones for the fuel system include:

1. Fuel System Control Module (FSCM) Fuse – This is a 25A fuse. It feeds the fuel pump flow control module . This is the primary fuse protecting the fuel pump circuit.
2. Fuel Pump Relay – In many GM vehicles of this era, the relay may be labeled "FUEL PUMP," "FP," or "FUEL INJ" . On the Acadia, look for a relay that is square or rectangular, made of black plastic, with 4 or 5 pins on the bottom . It will sit in a dedicated slot in the underhood block.
3. ECM and ECM 1 Fuses – These are 15A fuses that feed the engine control module . If the ECM is not powered, it cannot command the fuel pump relay on, so these matter too.
4. IGN Relay – This relay provides switched power to several circuits, including the airbag, PCM ignition, rear camera, and transmission fuses . If this relay fails, the fuel pump may not receive power.

If the diagram on the cover is missing, damaged, or unclear, consult your owner's manual . It will have a detailed diagram of all fuse boxes in your vehicle.

How to Test the Fuel Pump Relay and Fuse

Testing is straightforward if you follow a logical sequence. Always start with the simplest checks first.

1. Visual Inspection – Turn the ignition off. Use a plastic fuse puller (often stored inside the fuse box cover) to remove the FSCM fuse. Look at the metal strip inside the clear plastic housing. A blown fuse shows a visibly broken or melted strip . If it looks fine, move on.
2. Check for Voltage – With the ignition in the "On" position (engine off), use a test light to check for voltage on the two small test points on the top of the installed fuse . If you have power on one side but not the other, the fuse is blown.
3. Listen for the Pump – With the ignition on (engine off), you can command the fuel pump relay on with a scan tool. You should hear the fuel pump turn on and off . If you don't have a scan tool, have a helper turn the key to "On" while you listen near the fuel tank for a brief whirring sound. If you hear nothing, the relay, fuse, pump, or wiring may be at fault.
4. Test the Relay – If the fuse is good and you still have no power, the relay itself may be faulty. Swap the fuel pump relay with an identical relay from the same fuse block (such as the horn relay or fog lamp relay, if they are the same part number) . If the fuel pump starts working, the relay was bad.
5. Test for Continuity – For a more accurate diagnosis, use a multimeter set to measure continuity (ohms). Remove the fuse and place the meter probes on the two terminals. A good fuse shows near-zero resistance; a blown fuse shows an open circuit .

Common Symptoms of a Failing Fuel Pump Relay or Fuse

If the fuel pump relay or fuse is failing, you will likely notice one or more of the following symptoms:

1. Engine Cranks But Does Not Start – This is the most common symptom. The starter turns the engine over, but there is no fuel pressure to fire the injectors .
2. Intermittent Stalling – A failing relay can cause the engine to suddenly lose power and stall while driving, sometimes without warning .
3. No Fuel Pump Noise – When you turn the key to "On" (without cranking), you should hear a brief whirring sound from the rear of the vehicle. If you don't, the pump is not getting power.
4. Low Fuel Pressure – If the pump runs but the relay contacts are worn, you may get lower than normal fuel pressure, which can cause poor performance. The correct fuel pressure for the 2009 Acadia is between 384-425 kPa (56-62 psi) .

What Causes a Blown Fuel Pump Fuse or Relay Failure?

A blown fuse is a symptom of an underlying problem, not the root cause itself . Some of the most common causes include:

1. A Worn Fuel Pump Motor – As the pump ages, its internal components wear down, and the motor draws more current to maintain pressure. This increased draw can exceed the fuse's capacity and blow it .
2. A Short Circuit in the Wiring – If the wire insulation chafes against the chassis, the conductor can contact ground, creating a dead short that instantly melts the fuse element .
3. A Faulty Relay – A relay can stick closed or short internally over time, leading to unpredictable current spikes . Heat and vibration in the engine compartment can accelerate this.

If a replacement fuse blows instantly or shortly after installation, this suggests a persistent short circuit or a severely failing pump . In that case, professional diagnosis is recommended.

Steps to Replace the Fuel Pump Relay

Replacing the relay on a 2009 Acadia is a simple task. Here is how to do it:

1. Turn the ignition off and remove the key.
2. Open the hood and locate the underhood fuse block on the passenger side .
3. Remove the cover by lifting it. Set it aside.
4. Identify the fuel pump relay using the diagram on the cover or your owner's manual.
5. Pull the relay straight out with your fingers or a pair of needle-nose pliers. Do not use a screwdriver to pry it out.
6. Compare the old relay with the new one to confirm they have the same pin configuration and part number.
7. Push the new relay straight in until it seats firmly.
8. Replace the cover and test the vehicle by turning the ignition on and listening for the fuel pump.

Where Is the Fuel Pump Itself?

The fuel pump on the 2009 Acadia is not accessible from inside the cabin. Unlike some vehicles that offer an access panel under the rear seat, the Acadia requires dropping the fuel tank or accessing the pump from underneath the vehicle. The fuel pump attaches to the fuel sender assembly inside the fuel tank .

This is important to know because if you confirm that the relay and fuse are good but the pump is still not running, the issue may be the pump itself. Replacing the pump is a more involved job that typically requires either lifting the vehicle or dropping the fuel tank, and it often requires relieving fuel pressure and disconnecting the battery for safety .

Before you go down that path, check the harness connectors and the ground circuits of the fuel pump for poor connections . Loose or corroded connections can mimic a bad pump.

Why You Should Consider a KEMSO Fuel Pump

If your 2009 GMC Acadia needs a fuel pump replacement, you want a part that is reliable, built to last, and backed by a solid warranty. That is exactly what you get with KEMSO fuel pumps.

KEMSO fuel pumps are designed as high-performance, OEM replacement units. This means they are built to match or exceed the specifications of the original factory part, so you can be confident in the fit and function. Whether you are replacing a pump in your Acadia or another vehicle, KEMSO offers a range of options across many makes and models.

Every KEMSO fuel pump comes with a lifetime warranty. That is a strong statement, and it reflects the confidence the company has in its products. You do not have to worry about premature failure—if something goes wrong, KEMSO stands behind the part.

If you are in the market for a new fuel pump, KEMSO is a brand worth considering. You can browse their full catalog and find the right pump for your vehicle by visiting their website: https://www.kemsoracing.com/ . Their site includes a list of best sellers and a helpful blog with guides for many popular vehicles, so you can educate yourself before making a purchase.

Final Thoughts

Finding the fuel pump relay on a 2009 GMC Acadia is not difficult once you know where to look. The relay and its associated fuse are in the underhood fuse block, located in the engine compartment on the passenger side . Always check the fuse first, then the relay, before you assume the pump itself has failed.

If the relay and fuse check out fine, and you still have no fuel pressure, the problem is likely in the wiring or the pump itself. In that case, it may be time to consult a professional or replace the pump with a quality unit from a trusted brand like KEMSO.

Remember the golden rule: always turn the ignition off before removing or replacing any fuse or relay, and always use the correct amperage fuse specified in your owner's manual . Never substitute a higher-rated fuse, because that removes the protective function and risks melting your wiring harness .

For more information about KEMSO fuel pumps and to find the right part for your vehicle, visit https://www.kemsoracing.com/ .