A/C compressor clutch not engaging?

my compressor (new) won't stay on it will only engage with the A/C relay being jumped at the box. It has new A/C lines, condenser, and all switches new except the high pressure one at the compressor. I vacuumed before installing all parts. was able to get freon into system with relay jumped at the relay box and it got cold. I can make a video later it is late now, but I can if needed.