Door handle failures have been an issue for as long as Model S has been in production. There have been several revisions over the years but ultimately they still fail for a number of reasons. Gen 1 used a pressure sensor to "sense" when you pulled on the handle grip and these were the first thing to fail. Part #'s 1007372-00-A-G RF Gen 1 1007373-00-A-G LF Gen 1 1007374-00-A-G RR Gen 1 1007375-00-A-G LR Gen 1 ***Most Gen 1 Handles do not have any part number tags/stickers on them.***** Ribbon cable coming out of module and lack of 3rd microswitch is best way to identify these. Gen 2 changed to an additional microswitch instead of pressure sensor. Because the switches are on the moving linkage the stiff wire and brittle insulation tend to break or crack allowing in moisture and breaking the circuit. The Paddle Gear is also made of cast metal and the ears of the gear break off of the shaft and the door handle no longer presents. 1007372-00-H-L RF New 1007373-00-H-L LF New 1007374-00-H-L RR New 1007375-00-H-L LR New 1030273-S0-A/B LF Reman 1030274-S0-A/B RF Reman 1030275-S0-A/B LR Reman 1030276-SO-A/B RR Reman Gen 2.5 saw a new handle "chassis" but the same design for the microswitches and paddle gear. The only benefit is the handles "chassis" were no longer specific to front or rear doors just specific to Left or Right however modules were still location specific. The door shells themselves physically changed to accommodate the new style handle. (ex. LF handle couldn't be used as a LR even though it would physically bolt up) 1071881-S0-A RF New 1071880-S0-A LF New 1071884-S0-A LR New 1071885-S0-A RR New Gen 3 Cars were made after 7/24/17 deleted the microswitches in favor of a hall effect sensor, separate module, plastic vapor barrier and updated paddle gear design (still cast metal). The module seems to be the weakest link with this design but hasn't been out there long enough to say otherwise. 1100299-S0-A LF/RR New 1100300-S0-A RF/RR New The overwhelming majority of people fall in the Gen 2.0-2.5 category. For these door handles we have designed a Stainless Steel Machined Paddle Gear replacement and a plug and play replacement microswitch harness. The harness uses a combination of OE Panasonic Switches and Connector/Terminals with a softer more flexible braided wire and silicone insulation. The parts are available as individual pieces or as part of a complete kit including, upgraded gear, upgraded switches, door panel clips, vapor barrier retainers, and e-clip to secure the gear on the shaft. Provided you have a Version 2 or 2.5 Handle, We also can rebuild your door handle for you if you feel confident enough to remove it from the car but don't want to take it apart any further. You can also watch a good video on how to repair the door handle switches with Rich Rebuilds.