How to Change the Fuel Filter in a Chevy Trailblazer | It Fuel filters do get clogged, however, and will need to be replace usually every 24 months. Open the fuel door and remove the gas tank cap located on the driver's side of the vehicle. Pop the hood and locate the fuse box over the driver's side wheel. Use the diagram underneath the fuse box cover to find the fuel pump relay and disconnect it. Chevy TrailBlazer fuel filter location and replacement Nov 13, 2015Replace Chevy TrailBlazer fuel filter Remove the cap on the pipe that is attached to the fuel filter to release the remaining pressure on the pipe by pushing in with one screwdriver on the pipe tab. Some fuel will leak so you should have prepared a recipient for it.