Ac issues. Compressor wont engage by itself

Hi guys, ive been tryin to figure this thing out for a while. I havent had ac since ive owned this truck and have been obsessed with trying to get some. The compressor will work when i jump it from the battery but will not engage by itself. Ive check the ac fuse wich i believe doesnt actually control the compressor. Ive charged the unit several times and when i do i get a strange smell inside the cab and yesterday it looked like smoke or possibly steam? Any ideas on what could be the issue? Ive looked at all the wires i could and didnt see any bad wires. Im lost and could really use some help. The truck is a 3.4L 97 tacoma 4wd. Thanks

 

Evaporator is probably leaking. The compressor won't engage until the freon reaches a certain pressure.

 

Sounds like either the expansion valve or the evaporator core are leaking in the cab. Because they leak there isn't enough pressure to keep the compressor safety switch depressed.