Since we don't carry the Coleman brand I can't really speak to their quality but I can say that if you're wanting to only replace the rooftop units that the Advent Air Replacement RV Air Conditioner for Dometic Setup w/ Start Capacitor - 15,000 Btu # ACDOM150B would be a great option for you.
This particular unit comes with a wiring harness compatible with Dometic branded AC units so that installation is plug and play. The included start capacitor stores energy to help start the unit... view full answer...