Now for connecting wires, I'm going to describe it with pictures. If you have an existing Dometic AC, pop the filter off and look up in there to see how it is wired. Once you get the filter off, you'll see a grey box held in by two screws. The grey box is the relay control. Mine had the gateway stuck on top of it with double sided tape. The stuff I bought came with double sided tape so I set up the relay control and gateway for the new air conditioner the exact same way. Go ahead and remove the two screws holding in the relay control on your existing air conditioner because you will need to make some small changes in here as well. Just let it all hang down. You will wire the front AC the exact same way. You need to make some changes on the gateway for the rear AC! Don't skip these steps!
When you remove the rear relay control and gateway, note the position of the dip switch. #2 switch should be in the ON position. Do NOT touch the dip switches on the existing AC gateway! On the right, notice that there is a little plug with a jumper on it. REMOVE IT AND DO NOT LOSE IT! Now, look up in the hole for the existing AC and there should be a yellow cable in there with a four pin plug on the end. This is only if your RV is pre-wired for a second AC! Pull that plug down, and plug it in to the same spot where you removed the jumper plug!
This is how the existing gateway looks when you remove it. Remove the jumper pin on the right!
Jumper plug. DO NOT LOSE IT!
Find this wire up in the existing AC return air hole!
Plug it in.
Now you're done making changes to the existing AC unit. Don't power anything on yet.
Get your new relay control box (grey box) and your new gateway (black rectangular box). Go ahead and stick them together exactly as shown, with the double sided tape that came with them. You can also connect some of the wires here while it's not hanging from the ceiling! The gateway comes with a three wire plug. Go ahead and plug it in. The relay control comes with a four wire plug. Some of the wires have labels. Go ahead and plug that one in as well. Take the red wire coming from the gateway plug, and connect it to the red wire with white stripe coming out of the relay control. That wire also has a label that says "+12V to T-stat". Now take the green wire coming out of the gateway, and connect it to the orange wire coming out of the relay control. I shortened these wires and crimped them together. Finally, on your new gateway, take dip switch #1 and move it up to the ON position. It should all look like this when you're ready to install it. Note that you still have three wires on this assembly to hook up.
The relay control has a cover on the opposite side with four screws. Remove the cover and there are three wires in there. White, black, and green. Feed the romex cable into the clamp on the side and inside the box. Match up and connect the rome's wires to the three wires inside the relay control. I did some screaming and cursing during this step. Get the romex in the right spot and tighten the clamp on the side of the relay control. Look at your existing one if you need to. Replace the cover on the relay control.
Now, you have a green and white wire loop that should be fed out of one of the holes you drilled. Cut this in half. You will need to splice it back together since it powers things further down the line. But you also need to splice in those other wires you have left! So, take your two white wires you have now, strip the ends off the insulation, and connect them together with the black wire from the gateway AND the black wire from the relay control! That's four wires connected together. Crimp it all together. Now take the two thick green wires, strip the insulation off the ends, and connect both of them with the solid red wire coming out of the relay control box. All of your wire connections are done! Now you just have to plug a few things in!
What you do with the green and white wires. Should match the existing AC.
Note that on your existing air conditioner's relay control, there are two wires going into these two slots. You do not need them on your new relay control. They are for the furnace.
Remember the little jumper plug you didn't lose? Plug it in here on your NEW AC gateway! Note that the dip switch #1 is in the ON position! Also take four pin plug and two pin plug that you fed into the vent hole, and plug them in to the gateway as shown here.
Remember the wire that you jammed into the AC coil? Plug the blue plug into the relay control as shown.
Finally, take the big plug from the air conditioner itself, and plug it into the side of the relay control! Wiring is done!
Now is a good time to test everything out before you bolt the air conditioner down. Reconnect the battery and plug the RV in to power. It will take a minute for the InCommand to power up. There is a delay for the AC to come on as well. Make sure you flip all of the breakers back on as well. Select the new AC in your HVAC menu. If you have a zone temperature, that's a good sign! Turn the AC on. It might take a minute to come on. Assuming it does, you're good to go!
Now, take the mounting kit and figure out how high you need to mount the plate that comes with it. There is double sided tape on it already to hold it in the right spot. I also used some foil tape and added the white insulation that came with it.
This is the mounting kit.
Put it up like this and use the four long black bolts to thread up into the AC itself. Real easy to do. Feel the thickness of the foam gaskets on the rear AC, and make the front one about the same. I'd guess that you can overdo it here.
Use these two screws to attach the relay control to the mounting kit.
Like so. Then mount the cover and snap in the filter. Done! My AC vents blew out a lot of saw dust.
Snap the filter in and replace that white box that held your wires. Its only purpose now is to cover up that hole. I think Keystone could have done a MUCH better job with where they put that prewiring kit. The drilling and feeding wires was a real PITA.