Understanding the A/C system for a swap

[CMS-GT4]

What components are involved in kicking on the magnetic clutch on the compressor?

I want to try and finish my car over spring break, and I need to sort out a few things.

I am using the st205 A/C Idle up valve and A/C compressor with the 185 controls on it.

When I turn on the A/C the compressor clutch will not activate.

[Nitro_Alltrac]

There's an "AC Amplifier" under the dash. I ran into a similar problem on my son's ST. I could use a jumper wire and get the compressor and clutch to engage. Otherwise nothing. I ended up taking it to the dealer and the diagnosed the amplifer as bad. I got one off of Ebay pretty reasonable. May not be the problem, but something to check.