Knocking noise behind the glove box. I can reach my hand up and it feels like something is banging on the door. Mostly does it when weather is warm.

SOURCE: Module missing behind glove box

Probably the ECM, the main computer

SOURCE: 2 filters behind the glove box

Those are interior air filters that help clean any circulating air.

SOURCE: vent door stuck and can't remove glove box

why can't you remove the glove box? You can get at the door from under the dash but it's a ***** to do. try lubing the vent cables unless it uses the vacuum motor, if it uses the vac. motor it will be hard to get to without the glove box being out.

Testimonial: "Thanks! I just don't know how to remove the glovebox."

SOURCE: speedometer stopped working on 2004 trailblazer

There is no speedo cable on 04 T.B. all electric. You can get the stepper motors on line 6 of them thats what that board takes& thats how they sell them. I did mine you can check online for instructions. It is not that hard to do I took the speedo board to my computer shop & he did a great job soldering the 6 stepper motors to the speedo board. there is a GM mec. who gives detailed instructions how to do it. He is fed up with how many he has done. & GM Rip off price to do it. your dealer wants $ 250.00 to $500.00 to fix your broken speedo problem. 6 steeper moters $35.00 to $45.00 on line & $50.00 to solder them. Good luck.

SOURCE: There is a banging or knocking noise that comes

usually a knocking sound indicates that there is either a rod blown, if it is a ticking sound it could be your heads are not tight on enough.