Mercedes ML320 W163 Blend Door Motor Gear

thingiverse

This replacement gear will fit the blend door motor, which is known to break often (oem part number a1638200108). It's unlikely that this part would work with aftermarket motors. Before disassembling the item, flip the motor over and mark the position of the nub on the metal shaft. You'll want to reassemble in the same place. Four screws hold the motor together; remove them and it will come apart into two pieces. The top idler will come out easily. Next comes the metal shaft with the gear that needs replacement. The plastic gear will need to be pressed off carefully. Compare your new gear to the original gear. Tolerances are very tight on this part, so you may need to adjust its size. I printed this one using Inland ABS and the design accounts for normal ABS shrinkage. PLA is not recommended for this print. Print at 100% infill. Reinstall your newly printed gear with the flat side up. You should be able to push the gear onto the spline halfway with hand force, but installing it the rest of the way will probably require a press or a socket and hammer. If not, adjust the center hole size in the openscad file. Reassemble the motor assembly, making sure the metal nub on the bottom lines up with the mark on the bottom of the case. Grease the gears, reinstall the screws, and you're done. This uses the gear library found at https://www.thingiverse.com/thing:1604369/files. I've included the current version in case the library changes. Update: I have a report that this gear fits other GM vehicles, including the 2004 Blazer and 1998 Saturn SL2. Thank you to thall320578 for reporting back his success.