ac doesn't start

My ac doesn't work. I had check and there no power in position 30 of relay cut off ac.
When I put enero with s wire directly from battery in post 30 of ac cut off relay, it runs easy !
What the next point to check? Where is coming from the power to terminal 30?

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Have you tried jumping the low pressure cut off
I had to do mine to get my air conditioner to work