Saturn doesn't register drive door opening

[archan]

First time posting here, but have read the site over and through many times. Still, one question I can't seem to find anywhere, is that I have this Sega Saturn that doesn't register the drive being opened. Not a huge deal, but multi-disc games become unplayable after the first disc. Opening the beast up and toying around, i can't seem to see any mechanism that would tell the system "Hey, the door's open!". Would anyone have an idea on how to fix this?

[NFG]

There's a vertical post that the drive door, when closed, presses against.  It's mounted to the main PCB, and is located at the rear left corner of the drive door (when looking from the front-top of the system).

[l_oliveira]

To the drive there is 2 connections. One is a flat cable (data cable) the other is either a pair of connectors (20 pin flatcable, earliest Saturn type) with 4 pins and 2 pins connector (the 2 pins connector is the door sensing switch and 4 4 pins is power supply for the drive) or a 5 pin connector which is lid switch + power  for the console.

If you can measure the lid pin with a multimeter it connected to GND means door closed.  There might be a jumper under the drive board or the sense switch might had been modded with tape or a solder jumper / wire (for swap trick)

It should not be difficult to figure out what is wrong