Coleman-Mach 9420-391 WiFi RV Wall Thermostat, 12V DC Heat/Cool

The Coleman-Mach 9420-391 is the WiFi version of Coleman's 12-volt wall thermostat, built to run a rooftop RV air conditioner and a furnace from one digital head. You mount it on the wall, wire it to your Coleman-Mach system, and control heat, cool, and fan speed right from the LCD or from your phone. It's a single-stage control, so it handles one stage of cooling and one stage of heat, which covers the vast majority of RV setups out there.

The headline feature is the WiFi. Pair it to your home network or your rig's router, load the app on an Apple or Android phone, and you can check the cabin temperature and change the setpoint from anywhere you've got a signal. That's the part RVers actually use. Pull into a hot campground after a long drive and cool the coach down before you walk in. Or step away for an hour and keep an eye on the inside temperature from the picnic table. It's a small thing that turns out to matter a lot in July.

On the wall it's a clean digital unit with a black case and a clear LCD readout. It's programmable, so you can set a schedule and let it hold the coach at one temperature overnight and another during the day. The fan runs on high or low, and you can leave it in Auto so it cycles with the compressor, or set it to On so it runs continuously for steady air movement. Auto is what most people want. On is handy when you're trying to even out the temperature between the front and back of a long fifth wheel.

Because it runs both heat and cool, this one earns its keep across the seasons, not just in summer. In the shoulder months you're often cooling in the afternoon and calling for furnace heat overnight, and a single programmable head handles that swing without you getting up at 3 AM to flip anything over. Set the schedule once and the coach follows it. The LCD stays easy to read across the cabin, and the setpoint and current temperature are right there side by side, so there's no guessing what the system is actually doing.

Install is a wall-mount job on 12-volt DC, which is standard for Coleman-Mach systems. If you're replacing an older Coleman analog head or a basic digital one, the wiring generally lands on the same terminals, but always check your existing wire runs and the control box on the unit before you pull the old one off. Label your wires. Take a photo of the old terminals first. It saves a real headache later. This is a single-stage control, so it's the right match for a standard rooftop AC with an optional heat strip or a furnace tie-in, not a multi-zone or heat-pump-specific setup.

Who's this for? Anyone running a Coleman-Mach rooftop AC who wants app control and a schedule without stepping up to a full multi-zone system. It's a straightforward upgrade for a travel trailer, fifth wheel, or Class A motorhome with a single ducted or non-ducted air conditioner. It's not a multi-zone controller, and it's not the right part if your coach uses a heat pump that needs a dedicated heat-pump thermostat. If you're not sure which head your system takes, send us your model number and we'll confirm the fit before you order.

We stock genuine Coleman-Mach parts and we'll stand behind the fit. If the 9420-391 is the head your system calls for, it's a clean, modern upgrade that finally puts your rig's climate control on your phone. And honestly, once you've cooled the coach from the truck on the way in, you won't want to go back.