Question that turned into a problem

[GORDON HUMMEL]

I was in the process of redoing the towing wire harness. The original was cut for unknown reasons. When towing, I've had problems withe the toads batt going down, so I figured I could wire it to the coach to keep it charged. There was a brown wire in the original harness that I chose to use. I have the wire diagram from coach #281 and the brown wire is marked "pump"
Anyway that brown wire is attached to the relay in the attachment, but never gets any power. The 2 terminals attached to either side of the fuse are hot all the time. The white terminal on the lower right with the white wire is grounded to the mounting screw for this relay. The other 2 terminals + the brown never get power.
This AM I wanted to see that was powering the relay. I turned off the eng batt switch and the test light dimmed but did not go out. I checked again, & same thing.
Voltage with switch on 12.45; switch off 8.32.

Now I'm really confused

Any help is appreciated.