Replacing Fuel Pump In Trailblazer: Step-By-Step Guide

Replacing the fuel pump on a 2005 Trailblazer is a moderately complicated job, but it can be done at home. The fuel pump is located inside the fuel tank, and can be accessed by removing the rear driver's side seat and cutting a hole in the floorboard, or by removing the fuel tank from the vehicle. Before starting, it is important to relieve the pressure in the fuel lines by pulling the relay for the fuel pump under the hood while the engine is running. This will cause the engine to die. Next, disconnect the negative battery terminal and open the gas cap. The fuel tank can then be lowered and the fuel pump assembly removed. When reinstalling the new fuel pump, it is important to use a new rubber o-ring and to apply enough pressure to compress it. Finally, reconnect the fuel lines, electrical connectors, and battery, and check for leaks.

Removing the rear driver's side seat

To remove the rear driver's side seat of a 2005 Trailblazer, follow these steps:

First, move the seat forward and remove the two bolts holding the seat in place. Then, pull out the seat and set it aside. Next, remove the trim from the bottom of the rear driver's side door jamb and the B-pillar trim. Now, move the front driver's seat all the way forward to give yourself more room to work.

Locate the two nuts holding the rear driver's side seat in place and remove them. With the nuts removed, you can now lift the seat out of the vehicle. If necessary, you can make some inconspicuous cuts in the carpet to get better access to the nuts. Be careful not to cut any wires or damage other components.

With the seat removed, you can now access the fuel pump and continue with the replacement procedure.

Disconnecting the negative battery terminal

Park your Trailblazer in a safe and level area, and turn off the ignition. Place wheel chocks around the parking wheels for added safety. Open the hood and locate the negative battery terminal. It is usually marked with a "-" symbol or a black cover. Before proceeding, ensure you are wearing protective gear, such as gloves and eye protection.

Prepare the necessary tools: a wrench or socket that fits the negative battery terminal, and possibly a battery terminal puller if the terminal is tight. If you are using a battery terminal puller, place it onto the negative terminal and slowly turn the handle to loosen it. If you are not using a battery terminal puller, use your wrench or socket to loosen the negative battery terminal by turning it in a counter-clockwise direction. Be careful not to let the wrench or socket touch any other parts of the car, as this could result in an accidental short circuit.

Once the negative battery terminal is loose, carefully remove it from the battery post. Ensure that the terminal does not touch any metal parts of the car, as this could cause a short circuit. Place the terminal in a safe location away from the battery.

At this point, you may also want to disconnect the positive battery terminal, following the same steps as above, for added safety. With the battery terminals disconnected, you can now proceed with the next steps in replacing the fuel pump. Remember to re-connect the negative (and positive, if removed) battery terminal once you have finished working on your Trailblazer, ensuring to tighten them securely.

Removing the cross bar

To remove the cross bar, you will need to first pop the hood and access the fuse box. With the engine running, pull the relay for the fuel pump—the engine will die within a few seconds. Next, crank the engine a few times to relieve the pressure. Now, disconnect the negative battery terminal and then open the gas cap.

Using a short Phillips-head screwdriver, loosen the screw on the fuel filter. You will also need to press in on the Schrader valve to release any pressure in the lines. Gas may come out of the valve if there is still pressure in the lines. Have a container ready to catch any gas that comes out of the filter/line connections.

To disconnect the fuel lines, simply press in the clips (blue on the filter) and squeeze the other lines. No special tools are needed for these.

Now, place a jack and a piece of wood under the tank for support while you remove the straps. Loosen the hose from the tank to the gas filler tube. Using a small ratchet and a 7mm socket, loosen the straps using a size 15 socket, extension, and 1/2-inch ratchet.

Disconnecting the fuel lines

Before starting, ensure you have a fire extinguisher nearby as a safety precaution. First, depressurize your fuel system by pulling relay 41 under the hood and cranking the engine. This will help relieve any built-up pressure in the lines.

Now, you can remove the fuel lines from the fuel pump. Simply pinch the clip and pull the hose off. If there is rust, as there often is, you may need to wiggle the lines until they break off, making it easier to remove them from the fittings. Be cautious when performing this step, as gasoline may spill out.

At this stage, you will have access to the fuel pump. It is recommended to vacuum off any rust and metal pieces from the area before proceeding. This will help ensure that no debris falls into the tank when you remove the pump.

Next, you will need to remove the retaining ring that holds the pump in place. This can be done using a pneumatic hammer or a specialized tool. Once the ring is removed, the pump should come out easily.

Before installing the new pump, take the opportunity to clean the area thoroughly. You can use a vacuum to remove any remaining dust, small rocks, or debris. It is also a good idea to wipe down the area with a wet towel.

Finally, you can install the new fuel pump. Make sure to use a new lock ring and not reuse the old, rusty one. Reconnect the fuel lines and electrical connector, and you're almost done!

Start your Trailblazer to ensure that gasoline is no longer spewing out. If successful, you can move on to sealing the hole and reinstalling the trim pieces and rear seat.

Removing the straps

To remove the straps, you will need to place a jack and a piece of wood under the tank for support. Loosen the straps using a size 15 socket, extension, and 1/2 inch ratchet. Once the straps are removed, the jack/wood will help hold the tank. You may have to jiggle the rearmost strap to get it out of the way, but the front strap should come right off.

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