strange 2013 Chrysler T & C A/C issues

My A/C is not working, and has strange things happening. I first got a code that I had a faulty pressure switch, and so I changed it out. Didn't fix it. So I figured that I had a bad clutch, so I had a mechanic vacuum the system, I changed the clutch, then recharged it. Nothing. I then checked for power at the compressor with a test light and discovered that I have to power going to the A/C compressor to activate the clutch. But the strange part is that if I have the A/C system turned on, and I accelerate hard, the clutch engages for a few seconds, and then turns off again. I know it engages, because of how cold the air gets when it is 90 degrees outside, and the clutch is not in the same position as it was before I started the trip. So my questions are these. First, have you heard of this happening before? Second, I cannot find a relay for the compressor clutch on my year and model. Is there one and where would it be? And last, what and where do I check next to try and fix it?