A/C switch the engine is not rising the RPM?

Also, the engine is stalling because the A/C compressor is taking all power because the engine is not rising the RPM to run it.

Yep, these cars had a problem with the AC amplifier which runs the system, here is the location so you can change it out which should fix the problem. I would get a used one by searching eBay, check out the images (below). Please let us know what happens.

Thanks for you respond and I'll do as you say and get back to you.

I've just went to try back the car AC and I disconnect the AC amplifier plug and the AC compressor is still working blowing cold air, only the light that should be in the AC button gone when I disconnect the Amplifier.. so basically the fan switch turn on the compressor which I want to stop and work properly. Also once in a while the AC amplifier works

So you say the compressor works with the AC amplifier unplugged? Because the amplifier controls the compressor relay. I am wondering if someone has rewired the car? Please look at the AC system wiring diagrams below to see what I am talking about. Check out the images (below). Let us know what you find.

Yes that is what I'm saying. To my understanding someone who had the car before must have had it rewired so when the fan switch turns on the whole system compressor turns on and there goes the engine stall. I have to get a universal step-up valve to used. also, the idle control valve is malfunctioning, or it could be wiring problem because when I unplugged it sometime the idle get high and low it's not stable.

I'm guessing the connection run from the fan switch to the relay, once the relay removed no power is there and the AC amplifier disable to control the compressor that's what I think.

Yep, it sounds like the wiring got messed with, probably because of the bad amplifier so they tried to bypass it. I would try to put the wiring back to stock using the wiring diagrams above.

I'm definitely going to do that and thanks for your help I really appreciate it.

You are welcome, let us know how it goes.