2006 Mercedes ML350 Fuel Pump Fuse Location: A Complete Owner's Guide

If you drive a 2006 Mercedes-Benz ML350 and the engine cranks but won't start, the fuel pump fuse is one of the first things you should check. The fuel pump fuse for the 2006 ML350 is located in the luggage compartment fuse box on the passenger side of the cargo area, behind a removable cover . Specifically, fuse #43 (20A) powers the fuel pump, and there is also a fuel pump relay designated as relay "O" in the same fuse box . The engine compartment fuse box also contains a fuse (#105, 15A) that is tied to the fuel pump relay circuit and ME-SFI control unit . Knowing exactly where these components live and how to test them can save you a tow bill and a trip to the dealer.

This guide walks you through the exact fuse locations, how to access them, what symptoms point to a blown fuel pump fuse, and how to test the circuit safely. We'll also cover common reasons fuses blow and what to do when the problem isn't the fuse at all.

Where to Find the Fuse Boxes on Your 2006 ML350

The 2006 ML350 (W164 chassis) has multiple fuse boxes, and each one serves different electrical systems. For the fuel pump circuit, you need to focus on two locations: the luggage compartment fuse box and the engine compartment fuse box .

Luggage Compartment Fuse Box (Primary Location)

The main fuse box for the fuel pump is in the cargo area, on the passenger side. Here is how to access it:

  1. Open the rear tailgate.
  2. Look at the right-side trim panel inside the cargo area.
  3. You will see a plastic cover with two locking tabs.
  4. Twist both locking tabs to release them .
  5. Pull the cover off to reveal the fuse panel.

Inside this panel, you will find fuses numbered from 20 through 72, along with several relays . The fuel pump fuse is fuse #43, rated at 20 amps . It is clearly marked on the fuse chart that is also located near the vehicle tool kit in the cargo compartment .

The fuel pump relay is labeled as relay "O" in this same panel . The relay is a small cube-shaped component that clicks when the ignition is turned on. If the fuse is good but the pump does not run, the relay may be defective.

Engine Compartment Fuse Box (Secondary Location)

The second fuse box relevant to the fuel system is under the hood. It is located on the passenger side of the engine compartment . To access it:

  1. Open the hood.
  2. Locate the black fuse box cover on the passenger side, near the hood hinge.
  3. Pull the clamp in the direction of the arrow to release it.
  4. Lift the cover up to reveal the fuses .

Fuse #105 (15A) in this box is connected to the ME-SFI control unit and the fuel pump relay circuit . While this is not the main power feed to the pump, a short in this circuit can also cause fuel delivery issues.

Symptoms That Point to a Blown Fuel Pump Fuse

A blown fuel pump fuse rarely gives you a warning. The engine will usually stop suddenly or refuse to start. Here are the most common signs:

  1. Engine Cranks But Won't Start – The starter motor turns the engine over normally, but the engine never fires up. This is the classic symptom of no fuel pressure .

  2. Engine Stalls While Driving – The car dies while on the road and will not restart. This happens when the fuse blows intermittently or completely while the pump is running.

  3. No Fuel Pump Prime Sound – When you turn the key to the "ON" position (without cranking), you should hear a brief whirring sound from the rear of the vehicle for about two seconds. This is the fuel pump pressurizing the system. If you do not hear this sound, the pump may not be receiving power.

  4. Silent Fuel Pump – If you have a helper turn the key while you listen near the fuel tank, you should hear the pump run. Total silence indicates an electrical problem, not necessarily a dead pump.

  5. Hard Starting After Sitting – A failing pump or an intermittent fuse can cause long cranking times before the engine starts.

If you experience any of these symptoms, checking the fuel pump fuse should be your first diagnostic step. It takes less than five minutes and requires no special tools.

How to Check and Replace the Fuel Pump Fuse

Testing a fuse on a 2006 ML350 is straightforward. You can do it visually or with a test light.

Step 1: Turn Everything Off

Make sure the ignition is off and all electrical consumers are switched off. If the vehicle has Keyless-Go, open the driver's door to ensure the ignition is in position 0 .

Step 2: Access the Luggage Compartment Fuse Box

Follow the steps above to remove the cover on the passenger side of the cargo area.

Step 3: Locate Fuse #43

Look for the fuse labeled "43" – it should be a 20-amp fuse. It is located in the lower section of the fuse panel. Refer to the fuse chart near the vehicle tool kit if you cannot find it .

Step 4: Inspect the Fuse

A good fuse has a continuous metal strip visible through the clear plastic body. A blown fuse will have a visible break in the metal, or the metal may look melted or discolored. If the fuse looks intact but you want to be sure, use a multimeter set to continuity mode.

Step 5: Test with a Multimeter (Optional)

Set the multimeter to the ohms setting. Touch one probe to each of the two metal prongs on top of the fuse. A reading of near zero ohms indicates a good fuse. A reading of infinite resistance means the fuse is blown.

Step 6: Replace the Fuse

Use only a 20-amp fuse. Do not use a higher amperage fuse – this can cause wiring damage or a fire. Pull the fuse out with the fuse extractor tool located near the vehicle tool kit in the cargo compartment . Press the new fuse firmly into place.

Why Does the Fuel Pump Fuse Keep Blowing?

A fuse that blows once is often a random event. A fuse that blows repeatedly points to a real problem. The most common causes include:

  1. Short Circuit in the Wiring – The wiring harness that runs to the fuel pump can become chafed or damaged. Exposed wires touching the vehicle body cause a direct short, which melts the fuse instantly .

  2. Failing Fuel Pump – As the fuel pump motor wears out, it draws more current than it should. An overloaded circuit will trip the fuse. If the pump is on its way out, it will eventually blow the fuse even if the wiring is fine .

  3. Clogged Fuel Filter – On the W164 ML350, the fuel filter is part of a module located on the left side of the fuel tank . If the filter is severely clogged, the pump works harder to push fuel through, increasing current draw. This extra load can cause the fuse to blow.

  4. Incorrect Fuse Amperage – If a previous owner installed a fuse with a lower rating, such as a 15A instead of a 20A, it will blow under normal operating conditions. Always verify the amperage rating before replacing a fuse .

If the new fuse blows immediately, do not keep installing replacements. The underlying fault will only get worse. Move on to checking the relay and the pump itself.

How to Test the Fuel Pump Relay

The fuel pump relay lives in the same luggage compartment fuse box, labeled as relay "O" . A faulty relay is a common cause of a no-start condition, and it is much cheaper to replace than a fuel pump.

Testing Procedure:

  1. With the fuse box cover removed, locate relay "O" in the panel.
  2. Turn the ignition to the "ON" position (do not crank the engine).
  3. Listen or feel for a click from the relay. A single click indicates the relay is receiving power from the ignition circuit.
  4. If there is no click, the relay may not be getting power, or the relay coil is burned out.

Swap Test:

A practical way to verify a relay is to swap it with a known-good relay of the same type in the same panel. If the fuel pump runs with the swapped relay, the original relay is defective. If it still does not run, the problem is elsewhere.

What to Do If the Fuse and Relay Are Good

If the fuse is intact and the relay clicks, but the pump is still silent, the problem is either the fuel pump itself or the wiring between the relay and the pump. Here are the next steps:

  1. Listen for the Pump – Have a helper turn the key to the "ON" position while you listen near the right side of the fuel tank. The pump is located on the right (passenger) side of the tank . No sound means the pump is not running.

  2. Check for Power at the Pump – If you are comfortable working with electrical systems, use a multimeter to check for 12 volts at the pump connector while a helper turns the key on. Power at the connector but no pump operation points to a dead pump.

  3. Test the Pump Ground – A poor ground connection can also prevent the pump from running. Check that the ground wire has continuity to the vehicle chassis.

  4. Inspect the Pump Module – On the 2006 ML350, the fuel pump is part of the right-side sending unit module. To access it, you must fold the rear seat forward, remove a metal access plate, and disconnect the electrical and fuel lines . This is a job most owners can do in a driveway, but it does require care.

Replacing the Fuel Pump: What to Expect

If the fuel pump is confirmed dead, replacement is the only fix. The job involves:

  1. Disconnecting the battery ground cable.
  2. Relieving fuel system pressure.
  3. Folding the rear seat forward.
  4. Cutting through the sealant around the metal access plate.
  5. Removing the access plate.
  6. Disconnecting the electrical connector and fuel lines.
  7. Using a special tool to unscrew the lock ring.
  8. Lifting the pump module out of the tank .

A critical piece of advice: always replace the fuel tank seal (part number 1644700230 or 164470023064) when installing a new pump. Reusing the old seal will likely result in a fuel leak . The lock ring should be torqued to around 60–80 ft-lbs to ensure a proper seal.

The right-side module contains the fuel pump and a sending unit. The left side contains the fuel filter and a second sending unit. If your symptom is a no-start, the right-side pump is the culprit .

KEMSO Fuel Pump: A Smart Replacement Choice

When your 2006 ML350 needs a new fuel pump, the brand you choose matters. KEMSO offers high-performance fuel pumps that are designed as direct OEM replacements, built to meet or exceed the original factory specifications. Each pump is engineered for reliable fuel delivery and consistent pressure, so you can get your ML350 back on the road with confidence.

KEMSO fuel pumps are constructed with durable materials and tested for performance, making them a solid choice for daily drivers and long-distance travelers. The company stands behind its products with a lifetime warranty, which means you only buy a fuel pump once. If the pump ever fails, KEMSO will replace it. That is the kind of backing that gives you peace of mind on every mile.

Whether you are replacing the original pump or upgrading a worn-out unit, KEMSO provides a product that fits correctly and performs like the factory part. Many owners appreciate that KEMSO pumps are backed by a warranty that protects their investment far beyond what a typical store-brand pump offers.

To see the full lineup of KEMSO fuel pumps and find the one that fits your 2006 Mercedes ML350, visit their official website: https://www.kemsoracing.com/

Final Thoughts on the 2006 ML350 Fuel Pump Fuse

Knowing where your fuel pump fuse lives and how to test it can save you time, money, and frustration. The luggage compartment fuse box on the passenger side of the cargo area is the primary location, and fuse #43 (20A) is the one that powers the pump . The relay, labeled "O," sits beside those fuses in the same panel .

Start your diagnosis with the simplest checks: inspect the fuse visually, swap the relay if needed, and listen for the pump's prime sound. Most no-start conditions on the 2006 ML350 come down to a blown fuse or a failed relay. If those components check out, move to the pump itself.

Replacing a fuel pump is not a difficult job for a moderately skilled DIYer, but it does require patience and the right parts. Do not skip the new tank seal, and make sure you use a quality replacement pump.

When you are ready to replace the pump, KEMSO offers a high-performance, OEM replacement fuel pump backed by a lifetime warranty. Visit https://www.kemsoracing.com/ to see their available options and keep your 2006 Mercedes ML350 running strong for years to come.


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