Download the ECC Service Manual first. It will help make things below clear.
First, lets call the thermostat a TX for short. The front system is #1 the rear #2. Remove the jumper wire on Rh-Rc on both TX's as we want to isolate the circuits.
If you would like control of the high and low fan speed, you can put a double throw on off on switch in the circuit hooking one of the on terminals of the switch to low and the other to high and the center tap to the green terminal on the TX's.
Remember that the shedding will no longer occur, so you need to monitor how you use both A/C systems with the other coach requirements. That is the reason some are putting the rear A/C on a separate power cord that can be plugged into the 20 amp receptacle at the shore power station.
Front and Rear furnace
W on TX goes to either blue or black of PC4.(on TX#1 it will be the Wht/Blu and the Wht/Blk) (if you will note from your drawings, these two wires need to make contact for the furnace to function. The TX is the switch and controls the temperature. hook the other wire to Rh on the TX Do this for each thermostat for the front and rear of the coach. This completes the heating part of the project.
Cooling Rear A/C and TX#2
Connect red wire from pin #2 PC1A to Rc on TX#2
Y on TX to yellow wire #4 on PC3
G on TX to either Grn or Gry #3 or #2 on PC3 (You can put a double throw single pole on/off/on into this circuit if you want to have control of the high fan and low fan as a choice from the system.
ground pin #1 on PC3 (common blue) to pin #4 on PC1A
Cooling front A/C and TX #1
Connect red wire from pin #2 on PC1A to Rc on TX#1
Y on TX to yellow #4 on PC2
G on TX to gry or Grn #3 or #2 on PC2(can use same option as on Rear A/C)
Ground pin #1 on PC2 common (blue) to #4 on PC1A
This completes wiring for both front and rear A/C units, and isolaates them from the heating circuit.
Batteries in both TX's supply control voltage for the TX functions.
I hope this doesn't seem too confusing, but is rather simple.
Submitted by Gary Bogart
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