Oil pan, bottom of engine. There is a plastic cover over it. Take off the small plastic cover.
Under the dash
The 2005 Chevy Trailblazer has Coil-On-Plug ignition coils so there are 6 "coil packs". Each one is mounted on top of the spark plug.
In a 2002 trailblazer it is located on the bottom of the radiator one the passenger side. Every other model year to my knowlege does not have drain plug.
Should be on the rear or side of the oil pan
The 2006 Chevy Trailblazer passenger side rear freeze plug is located near the back of the engine block. The freeze plug will be near the bottom of the engine block.
spark plug
.043
AC Delco iridiums
15mm
If the car will not start...the spark-plug is bad.
the drain plug is located on the back side of the oil pan under the car.
Turn it to the left.