Originally Posted by geoffmboyd
Diagram was helpful. I couldn't splice it back the way it was because I needed to remove wired alarm. However, i plugged harness clip back in with two red wires joined by wire cap and everything worked fine. I put a cap on the yellow/white wire to just be super safe, but downstream sensors must have their own common white wire. The downstream sensors won't work if you just unplug the wired alarm at the connector clip because hot wire runs through the alarm itself (I tried even before first suggestion in this chain) - but if you connect the two red wires everything is good to go. Thanks for responses.
That is interesting. I took a look at my Interstate today and realized that I just disconnected the old alarm at the connector. Everything on mine still works normally after replacing the CO alarm with a battery only unit of the same brand.
This contradicts what I said in my first post above so I took a closer look at the wiring diagrams I have. The yellow wire is just a ground (-12VDC) point for the CO alarm. The two red wires appear to come from different +12V sources. One to Circuit #6 on the Coach 12VDC Distribution Panel. The other connects to the Chassis battery side of the BIM relay. This makes sense so the alarm is always powered even when the Coach battery is disconnected. See additional wiring diagram snapshots I've attached.
By tying those two red wires together you may have inadvertently connected the two batteries together. Unless of course your Interstate is wired differently than the 2015 and 2103 wiring diagrams I'm using.
Have you just disconnected the old wiring to the CO alarm at the connector in the overhead above the alarm and seen what you have on Tank Monitor Panel? Try that if you haven't already.
Also recommend you check each of the three wires to make sure they follow the Airstream wiring diagrams. There maybe a wiring anomaly in your Interstate. A Multi-meter would be the best way to do this if you have one.
I don't recommend you leave the two red wired connected if in fact they are each coming from a different battery source.