Replacing Fuel Pump Relay In A 2005 Mercedes E320: Step-By-Step Guide

The fuel pump relay on a 2005 Mercedes E320 is located in the rear fuse box in the trunk. It is the bottom relay in the fuse and relay box. The fuel pump is located inside the fuel tank on the right side.

The fuel pump relay is located in the rear fuse box in the trunk

To access the fuel pump relay, you will need to remove the rear seat cushion. There are locking mechanisms underneath each front corner of the seat cushion that need to be pressed to release it. Once the seat cushion is removed, you will be able to locate the fuse and relay box.

It is also worth mentioning that Fuse 4 in the rear fuse box powers the fuel pump. This fuse should have power at all times. If there is no power to Fuse 4, it may be necessary to replace the rear fuse box or the rear signal acquisition module.

The relay is the bottom one in the fuse and relay box

To change the fuel pump relay on a 2005 Mercedes E320, you will first need to locate the relay. The relay is located in the rear fuse box, which is in the trunk. The relay is the bottom one in the fuse and relay box.

To access the fuse box, you will need to remove the rear seat cushion. There is a locking mechanism underneath each front corner of the seat cushion that you will need to press to remove it.

Once you have located the fuel pump relay, you can test it for power by cranking the motor. If there is no power, you will need to replace the relay. You can also test for power to fuse 4 when cranking the motor, as this fuse powers the fuel pump. If there is no power to fuse 4, you may need to replace the rear fuse box.

You can test for power to fuse 4 when cranking the motor

To test for power to fuse 4 when cranking the motor of a 2005 Mercedes E320, you will need to use a circuit tester, also known as a test light. This will allow you to check for power at the fuse and determine if there is an issue with the relay or the fuel pump.

First, locate your fuse box. For the 2005 E320, the fuse box is located in the trunk, or rear of the car. You will also need to remove the rear seat cushion to access the fuel pump and relay.

Next, connect the grounding clip of your circuit tester to a bare metal point on the vehicle, which will serve as your ground point. A good ground point is usually the negative terminal on the car battery. To test if your circuit tester is working, connect the ground clip to the negative terminal and the tip of the probe to the positive terminal. If your circuit tester lights up, it is functioning properly.

Now, you can test for power at fuse 4. Touch the tip of the circuit tester to the exposed metal prongs on both sides of fuse 4. You should have 12 volts of power to the fuse when cranking the motor. If there is no power, the issue may be a bad rear fuse box, a bad relay, or a faulty fuel pump.

If fuse 4 has power, the next step is to test for power at the fuel pump. To do this, you will need to remove the rear seat cushion and access the fuel pump. You can refer to the provided instructions for removing the rear seat cushion and accessing the fuel pump. Once you have accessed the fuel pump, you can use the circuit tester to check for power. Touch the tip of the circuit tester to the appropriate terminal on the fuel pump. If there is no power, the fuel pump or the relay may be faulty.

If there is power at the fuel pump, the issue may be with the fuel pump itself. In this case, you may need to replace the fuel pump.

The fuel pump is located inside the fuel tank

To access the fuel pump, you will need to remove the rear seat cushion. This is done by pulling up on a small plastic release lever in front of the cushion. Once the cushion is folded forward, you can remove the carpet below the seat by pulling it up at the corner to detach the clip.

With the carpet removed, you will expose two access covers. You will need to remove the cover on the right side (passenger side) to access the fuel pump. There are six 8mm access cover fasteners that need to be removed. After removing the cover, you will need to unscrew the fuel pump module threaded collar. This can be done with a special tool or a brass punch and a rubber mallet.

Once the collar is removed, gently lever the top of the fuel pump module up to free it from the tank seal. Slowly lift the fuel pump module top up and remove it, and then pull the seal out of the fuel tank. You will then need to remove the lines and electrical connectors at the fuel pump module.

It is important to note that you should always catch any dripping fuel with a cloth and place the fuel pump module in a bucket or plastic bin to minimize spilled fuel. Additionally, it is best to replace the fuel pump with the fuel tank drained to reduce the risk of spills and vapors.

The fuel pump relay is located under the rear seat cushion, next to the battery

To change the fuel pump relay on your 2005 Mercedes E320, you'll first need to locate it. The fuel pump relay is located under the rear seat cushion, next to the battery.

• Remove the rear seat cushion: There should be a locking mechanism underneath each front corner of the seat cushion that you need to press to release.
• With the seat cushion removed, you will see the carpeted floor. Pull up the carpet at the corners to detach it and expose the body floor.
• The fuel pump relay is located next to the battery. It is usually held in place by a fuse panel or a plastic cover. Remove the cover to access the relay.
• Once you have located the fuel pump relay, you can proceed to replace it with a new one. Ensure that you purchase the correct relay for your vehicle.
• Compare the new relay with the old one to make sure they match.
• Disconnect the old relay by pulling it straight out of its socket.
• Insert the new relay into the socket, ensuring it is securely connected.
• Reinstall the plastic cover or fuse panel, if removed.
• Place the carpet and rear seat cushion back in their original positions, securing them in place.

By following these steps, you should be able to successfully change the fuel pump relay on your 2005 Mercedes E320.

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