[Richard]

Lets cover in concept what this modification does. The mod takes the high current of the compressors of of the circuit boards and runs the compressor current through external relays. The two small terminals(A1 and A2) on either side of the contactor are the terminals for the contactor coil. When they see 120VAC the coil will energize and pull the contacts together. The trigger for the contactor is the voltage that normally would go to the compressor. By cutting the two wires from the board to the compressor, the wires are extended and used to trigger the contactor.

The two large terminals (L1 and T1) are designed to carry heavy wire and heavy current. One side, usually L1 will be wired to one of the hot legs of the coach AC system. The other side, T2 will be extended to connect to one of the two wires going to the compressor.

The second wire going to the compressor will be wired to neutral. It doesn't matter which since this is an AC circuit.

This is how to execute the concept.

Ok, A1 and A2 are the trigger for the relay coil. Run the two wires FROM the compressor output on the board to those terminals. You can use small wire since the current is about 0.3 amps. The two big terminals are L1 and T1. On one side of that you will wire either black or red hot 110. On the other side run the output to one of the two wires going to the compressor.

Remember, looking at the diagram that you also have to run neutral (white) to the other compressor wire to complete the circuit. Neutral does not go through the relay.

When you wire the second compressor, use the hot source that you didn't use on the first relay. That keeps the two compressors on separate legs to balance the load.

The board still requires all of it's 120VAC connections to power the circuitry and the fans.

The second thing to remember is that when you do the second unit. If you used black to power the first compressor on unit 1, then use red to power the first compressor on unit two.