Some common Chevy Trailblazer problems include issues with interior electrical accessories. The main problems occur in a malfunctioning fuel gauge and speedometer, which are located in the instrumental panel.
A malfunctioning fuel gauge is usually due to a faulty fuel tank sending unit. The sending unit is located in the same area as the fuel pump or close to it. In order to fix the fuel tank sending unit, it will need to be replaced.
A malfunctioning speedometer is usually due to issues in the vehicle's speed sensor, which is located on the transmission. The unit will need to be replaced in order for the speedometer to work again.