If you have a driver information center you can scroll through the menu. If not then it is the old fashioned way ...... fill the tank ...... set your trip odometer and watch the gas gauge.
The 2004 Chevy Trailblazer is equipped with an oil pressure/sender switch that is just to the left of the distributor. It is in the front of the manifold. This device takes the place and function of the oil pump.
Turn it to the left.
The VIN, or serial number is permanently stamped into the left frame rail behind the left front wheel of all Polaris ATVs.
If your Trailblazer is a 4x4 the switch should be to the left of the radio on the dash.
Not 100% sure about the 2004, but in the 2005 it is inside the square box just left of the engine. (air suply tube goes into the top of the engine). You need to unscrew the box to take it off.
It is located on the left side of the engine (6cyl) next to the thermostat, in order to replace both thermostat or sensor the alternator needs to be removed
The PCV valve on a 2006 Chevy Trailblazer is located on the top, left side of the engine. It allows gases which are built up in the engine to be recirculated.
front left of engine facing radiator.
Its under the fuel tank in the back left of the car to measure how much fuel is still left in the tank.
Remove the air chamber labled Vortec 4200, two bolts on left side, and loosen the hoses on both sides. No cables!, remove bolts of each coil pack and plugs are below...
The cam sensor is located on the left side of the engine (as your looking at it) on the valve cover
Left side at the front on the car there is a diagonal brace. under that is a plastic box that is your air box.