You can buy a shop repair manual. Haynes or Chiltons are the preferred choices as they are your less expensive options.
Engine diagrams can be used as guides.. An engine diagram to a 2003 Chevy Trailblazer can be found in its maintenance and repair manuals.
We have complete instructions and pictures at our enthusiasts website www.trailvoy.com
This answer will vary with what's wrong and which shop looks at it.
The throttle body needs to be cleaned. Instructions are on our forum at www.trailvoy.com
Value of a 2003 Trailblazer w130,000 miles
how unlock radio on trailblazer 2003
buy a haynes repair book at your local parts store it has detailed instrutions
It pulls off. Sometimes easier to remove the headlight assembly to change the bulb. We have instructions at our forum. www.trailvoy.com Trailblazer enthusiasts!
It could be coming from your heater core, may need to repair or replace it.
Where is the input aux for a 2003 trailblazer
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It sounds easy but it takes some time. We have complete instructions at our enthusiasts forum at www.trailvoy.com