Purpose of plug right under the fuse box? is it AC? (PICS)

[thedeepfield]

Hello,

I'm in the middle of an sr20 swap into my 91 240sx and im trying to get my AC to work. It was working before the swap but now the green AC light on the climate control unit doesn't even turn on. I noticed that there is a 2 wire female plug right under the fuse box, and nothing else plugs into it except for another 2 wire male plug that's attached to the AC dryer plug. Even after plugging it in, the AC light doesn't turn on.

So my question:
-What is the plug right under the fuse box used for? People are saying its the neutral position switch or something...
-Does there need to be refrigerant in the AC system in order for the AC light to turn on? if so, can I use those do it yourself kits?

Images:

2 wire male plug connected to AC dryer plug


2 wire female plug right under fuse box



routed 2 wire male plug to be next to 2 wire female plug right under fuse box... looks like they fit...


Plugs right in, but no AC light...

[Jmoore124]

There does not need to be coolant in the system for it to turn on. My suggestion would be to turn the ac on and see if the compressor clutch activates. You will be able to tell this by hearing a slight drop in rpm and if you are looking at it the whole pulley will move not just the outside. If it isn't then your problem is likely with the pump clutch control wire. You can trace the one wire that goes into the compressor pulley area and figure out why its not receiving power. Hope those pictures help you. I would go to the top of this forum and download the FSM for your car and go through the ac diagnosis procedure.

Its not the neutral switch by the way. If I had to take a guess I would say its the alternator, judging by how large they are.