I'm going to try to start a thread for things I've learned that can help with the amazing number of quirks that the G37 Hardtop Convertible has. I have three to share

First, if a flapper stops working, you can replace what is very often the broken gear that is the problem. I'm convinced if you take on this job you should contact Guy Menard and buy a pair of his custom made, all metal gears. Here is a YouTube post I found very helpful in doing this work:
If you convertible top seems to have died--no movement, no beeps, no anything, disconnect the negative battery cable and let the car sit for a while and then put the cable back on. Fixed my wife's latest problem with her G37 which I an convinced is haunted or possessed or both. Because it's always something. See the next one

If your drivers side door loses its mind and the window won't behave after you get out, as is common when you disconnect the batter, try the following:The G37 Convertible (and other Infiniti/Nissan models with frameless windows) features an "automatic indexing" function. This system is designed to drop the window slightly when the door is opened to clear the roof/seal, and then raise it back up to create a tight seal once the door is closed. When this fails to happen—often after a battery disconnect or a power-related issue—the window will leave a gap at the top. You can typically fix this with a simple window reset procedure.

How to Perform the Window Index Reset--There are a few variations of this procedure, but the following is the most commonly reported method for the G37:

1. Close the door completely.
   
2. Operate the window switch to roll the window all the way down and keep holding the switch for a few seconds after it reaches the bottom.
   
3. Roll the window all the way up by pulling the switch, and once it hits the top, continue to hold the switch up for about 5–10 seconds.
   
4. Release the switch and test it. The window should now "index" (drop and raise slightly) correctly when the door is opened and closed.
   

If that doesn't work, try the "auto-pinch" reset variation:

1. Lower the window halfway.
   
2. Pull the switch up to close it without triggering the "auto-up" feature (if possible, by pulling it only to the first click).
   
3. Once it is fully closed, hold the switch for 5 seconds.
   
4. Test the auto-up/down functionality.
   

Other Potential Causes

If the reset procedure does not resolve the issue, consider these possibilities:

• Battery Issues: A weak or failing battery can cause the window control module to lose its calibration or fail to provide enough consistent voltage to complete the cycle.
  
• Door Seals: If the rubber seals around the door frame have become stiff, dirty, or misaligned, the window might encounter too much resistance, causing the "auto-pinch" protection to trigger and stop the window from closing fully. Cleaning the seals and using a silicone-based lubricant can sometimes help.
  
• Window Regulator or Motor: If you hear grinding or clicking noises, or if the window moves unevenly, the regulator (the mechanism that moves the glass) may have a broken cable or worn-out plastic clips.
  
• Electrical/Fuses: While less likely if the window still operates, a failing door-ajar switch or a blown fuse can sometimes cause erratic behavior.