Here is a diagram of the AC without the colored wires that are labeled and it is clearer. It also shows the circuit without the anti-dieseling relay.
I see that it does not show a power wire on the B terminal of the switch, perhaps because the AD relay is missing. The power wire in that case would almost have to be the same orange wire that goes to the fan relay.
check the legend on the left side of the diagram and see the switch positions for the different speeds.
By the way -Kudos to you for your detailed description of your problems.