The tools you'll need: long Phillips screw driver, long T20 torx (strongly recommend a magnetized tip to prevent pre and post cursing), flash light, needle nose pliers, flathead screw driver.
Step 1: Remove glove box by removing the 6 Phillips screws.
Step 2: Remove the lower tray behind the glove box.
Step 3: (some people like to remove the vent housing but its not necessary. Working around the vent is better than fighting the installation of the vent) Remove the stepper motor by releasing the two T20 torx screws, pull the stepper motor assembly out slightly and remove the linkage with needle nose pliers by twisting the pliers (see image). Unplug connector to stepper motor and move out of the way.
Pull stepper motor assembly out to access the linkage arm
Step 4: Remove the two T20 torx screws from the final stage resistor (In most cases, the screws will be missing) Pry the black plastic clip back with a flathead screwdriver (see image) and pull out the resister. The resistor will sometimes fight you so try to wiggle and pull out the resistor simultaneously while prying back the black plastic clip.
Use a flathead screwdriver to pry back on this plastic tab to release the final stage resistor from the HVAC case
Step 5: unplug resistor and install new resistor in reverse order
Final stage resister
List price from dealer $120.00
Works with E46, E53, E85 and E83