This is precisely what I do not understand: With the switches I have with P3D that recognize the doors open and close normally. GSX but seems not to recognize the open
As I've said, GSX reads the variables used FROM THE SIM. So, the only possible explanation for this, is those variables are NOT set in the sim for some reason.
If you use a 3rd party airplane with an internal simulation of systems that might not relate to the variables used by FSX, it's possible that your script has made the door "visually" open, but it caused losing the sync between the sim and the plane internal simulation.
For example, you might have modified the visual status of a door's animation, but the sim might have a separate status for it, based on another system, for example the electrical power and, if you modify something like that, the plane simulation might be confused.
That's why we decided NOT to have GSX trying to opening doors itself automatically: it's too dangerous touching the state of a simulation you might not know much about, so we only READ variables, and never try to WRITE them.