I had a shot blower resistor pack (no 1,2 or 3 speeds on the blower) so I ordered a replacement unit. It arrived today and I put it in just now. I looked around and did not see a "how to" on it, so maybe this will help some others.
2002 Trailblazer LS - no automatic temp controls
about 20 minutes (spent time getting the right stuff from the garage
blower motor resistor (I used parts4chevys.com so I used the drill down menu to find it, sorry I do not have the PN handy)
7mm socket or nut driver
7/32" socket or nut driver
one long screw driver (flat blade) - optional
flash light - optional
locate the two 7mm screws holding the plastic kick plate under the passenger side dash, remove them, and then carefully remove the plastic cover
look up under there and you can see the old resistor pack. It has one connector and a pair of wires going from it. Unscrew the two 7/32" screws and it will come down, unclip the wire harness
open the glovebox and empty it, now release the catch so that it can hang down
locate the end of the wires that came from the resistor pack, they are plugged into the blower, release the clip and remove them (I used a screw driver to push in on the little clip to release it)
reverse the process and install the new one
here is the comparison of the two
hope that helps somebody....
From the Roadie: Since everybody looks in this post if they use a search, I'm just going to add the schematic HERE for one-stop shopping