You need to change the fuel filter in your Chevy Trailblazer every 30 months or 30,000 miles. On the 2005 model Trailblazer, the fuel filter is mounted with a bracket on the fuel tank, as is the case with most recent models. The fuel system is under high pressure, so use extreme caution; also, don't start the vehicle after replacing the filter until you have cleaned up any fuel that may have spilled.
Disconnect the fuel pump relay from the engine compartment's fuse box; the diagram under the fuse box lid will show the relay's location. Remove the filler cap on the side of the vehicle, run the engine until it stalls and then crank it for another five seconds to relieve all fuel pressure.
Disconnect the negative battery cable--loosen the clamp nut with an insulated wrench.
Raise at least the rear end of the truck and support it on jack stands. Raising the entire truck on at least four stands will give it better support.
Clean away dirt and other debris surrounding the fuel-line fittings at the filter using compressed air.
Disconnect the fuel lines from each end of the fuel filter, using your fingers or needle-nose pliers to disconnect the quick-connect fittings for each line. Wrap rags around the fittings or have a container underneath them to catch spilled fuel.
Unscrew the fuel-filter bracket from the tank; if you have a four-wheel drive truck with a tank shield, look for a small hole in the shield to access the mounting screw.
Squeeze the ends of the fuel filter's clip together and remove the filter from the line.
Connect the replacement fuel filter to the line--most new filters will have a new clip already installed--and connect the bracket to the tank using the mounting screw.
Connect the inlet and outlet lines to the filter using the quick-connect fittings.
Lower the vehicle off the jack stands.
Reconnect the negative battery cable and the fuel-pump fuse.
