Intermittent A/C compressor

1st Gen Tacoma compressor intermittently failed to engage shortly after compressor replacement. Changing fan speed would get it going at first, but now it won't go at all. I can hear clicking behind the control panel when A/C button is pressed and the idle speed increases. What is the location of the amplifier?

 

Have you checked for power at the compressor when it's not working? If not I'd start there, I have seen connector issues on aftermarket compressors.
The A/C Amplifier is built into the control head on 1st gen trucks.
You say the idle speed increases when you push the button, that tells me it's getting all the proper signals and trying to turn the compressor on.

 

That was it. Fixed with no parts. Just tuned-up the connector a bit. Thanks for the advice and especially the schematic.