[Richard]

We are in the hinterlands of New Hampshire, so my interweb connection is flaky. I cannot download your attachments.

I just got your version of the schematic downloaded. DO NOT wire the setup to that schematic. You are connecting hot to neutral in the contactor and you will created a dead short.

I am not necessarily known for diplomacy, so take this with the good spirit intended. You might want to watch a few U tube videos of how to read a schematic and some on how relays work before you wire anything up.

That being said, let me take a crack at explaining what you are doing. Presently the current and voltage to run the AC compressors runs through the board. The purpose of the external relays is to take the voltage and current for the compressors and offload the voltage and current to external relays. We are going to use heavy duty relays (otherwise known as contactors) with 120V coils.

We are going to use the schematic to find the two wires from the control board to the compressor. Snip those two wires into. Think about what we have when we do that. The wires coming from the board will have 120V on them when the board tells the compressor to come on. The board does not know the wires have been snipped. Use those two wires to energize the coil in the relay. When the coil is energized, the big contacts will close in the relay.

But, more connections need to be made to get power to the compressor. The two leads that were snipped to the compressor are hooked to nothing at this point. The hot lead will go to the contactor, the neutral lead needs to be tied into neutral. But the compressor still has no power because there is no HOT going into the contactor. The HOT coming from the coach (Black or Red) should be connected to the other side of the contactor.

When this is done, the board will send 120V to the coil of the contactor, since one side of the contactor is connected to the hot (black or red) side from house power, and the other side of the contactor is connected to the hot input of the compressor the compressor will now have a hot leg. Remembering the neutral to the compressor is tied into the neutral, the circuit will be complete and the compressor will start.

If this is not comfortable to you, you may want to think about hiring an electrician. Miswiring could harm the compressor, the control board, or most importantly you.