When must Mum bought her new N13 back in 1989, when you put it in reverse the A/C cycled on. This was apprentice to keep the gas circulating and keep seals from drying out. That sounded like a good idea to me. However it seems following models, nor any other car I've ever had, did this. We always wondering why.
These are the only reasons I cam think of why it isn't done now.
1. You weren't in reverse long enough to make any difference to the A/C system.
2. Confused too many people as to why the revs increased.
3. Maintained the system so well that Nissan lost out on spare parts sales.
4. Gas is always in contact with all seals so it was a waste of time/energy anyway.

So, any ideas? Thanks.