So you did check the connection under the car?

 

I think he’s saying there’s no power to the gray wire anywhere. The pump only works when he jumps power to that gray wire. He said “probed” the wire. I take probed to mean he applied 12 volts.
Since that gray wire goes directly back to the relay, that’s where he needs to look. I would recheck the relay. Swap it out with a known good one and see if it works.