E90x HVAC Blower Motor Replacement
This DIY is meant to augment the Bentley repair manual for replacement of the heating/AC system blower unit for the E9x. The Bentley manual directions for replacement of the blower unit are totally screwed up and will make you take twice as long to replace the blower than it should. It’s good for looking at the pictures and that’s about it. It even shows the incorrect direction to remove the blower unit!
The blower unit is not secured in place by screws, or bolts, like you think it would. The blower unit fits within a big hole within the HVAC housing and just twists into place. It is removed by hand; no tools are needed to remove the actual blower unit. Tools are needed to remove the panel to get to the blower unit and swap out the motor controller.
As usual I don’t take pictures when working on my car, but I try to be descriptive enough so you won’t need them.

I've included a MS Word version that is properly formatted...

Here are the proper instructions:
Tools needed:
Flashlight
Drop light
T-20 Torx screw driver
Mechanics Dental Pick.
Basic procedure:
1) Remove the passenger side lower dash panel.
2) Disconnect the power connector to the blower.
3) Remove the right-side heater duct work.
4) Remove the blower unit.
5) Swap the motor controller electronics from the old to the new unit.
6) Re-install the new blower unit.
7) Re-install the heater duct work
8) Re-install the lower dash panel.
Instructions:
1) Remove the Passenger side lower dash panel:
a. Slide passenger seat all the way rearward
b. Look under the glove box door and you will see two, black, torx (T-20) screws. Remove them.
c. Pull the lower dash panel down and rearwards and pull it halfway out.
d. Disconnect the power lead to the footwell light.
e. Remove the panel.
2) Disconnect the power connector: On the blower unit you will see a white plastic electric motor controller unit that has two connectors. One connector is for power from the body to the controller, the other connector is from the controller to the blower motor. Disconnect only the connector that feeds into the body cable. It disconnects by squeezing the black tabs and pulling straight down.
3) Remove the right-side duct work: The duct sits right behind the hinge for the glove box door and ha three feed holes. At the end of the duct (third feed hole) near the center of the footwell, gently pull the duct straight down about an inch (it snaps onto part of the blower housing with a metal toothed clip – it comes off easily). Now, pull the duct piece straight out from the center console towards the right side of the footwell. It will snap out of place. A second, smaller duct piece will probably come with it. This piece feeds the air into the rear seat duct work. It snaps on to the larger main, front footwell duct.
4) Remove The Blower unit: (This is where the Bentley procedure goes awry). The blower unit just twists in and out of place. There are two tabs on the perimeter of the blower unit housing. One tab is in the front near the white part number label. The front tab is an indexing tab to make a stop for the blower unit when twisting it into place. The second tab is in the rear of the blower near the fire wall and is hidden above the big, inch-thick, wire harness running along the firewall. The second tab is a locking tab meant to keep the blower from rotating out if it’s hole once it is in place. It’s hard to see the locking tab and hard get a hand on it. You will most likely break the rear tab off while removing the blower and replacement unit will probably not have the tab on the housing (because it was broken off already if it is a refurbed blower unit.
a. Once the duct is removed, find the rear locking tab and pull it down using the dental pick.
b. While the locking tab is pulled down twist the blower unit counter-clockwise (as you are looking up at it when on your back under the foot well).
5) Swap out the Motor Controller:
a. The motor controller is white and mounted to the blower unit housing. On the old blower unit, disconnect the second connector that feeds power to the blower motor. Remove the two silver screws (T-20 Torx) that mount the controller to the housing.
b. Install the old controller on to the new blower unit using the screws. Reconnect the connector.
6) Re-install the new blower unit:
a. Put the new unit up into the big opening in the HVAC housing. Rotate the blower unit clockwise until it locks in place with a click.
b. Reconnect the power connector from the main body harness.
7) Re-install the heater duct work:
a. Put the large ductwork piece back in first until it snaps into place.
b. If the small duct came out when taking the duct apart, re-install it now. You’ll have to move a wire harness that runs along the transmission tunnel and pull a part of the console trim out a little bit to get the little duct back into place.
8) Re-install the lower dash panel:
a. There is a large clip molded into the dash panel that slides into a slot on the lower dash, so make sure you get the clip into the slot.
b. Now re-connect the footwell light connector and push the panel back towards the firewall.
c. Rotate the front of the panel upwards to align the screw holes and re-install the screws that hold the panel in place.
Addendum:
If your new blower unit came without the locking tab you can secure the unit using the front index tab. The index tab lines up with a hollow bung on the HVAC housing that you can install a small wood or sheet metal screw into to keep the blower from rotating out of place (I doubt it ever would anyway).