Step-by-step wiring guide for replacing your Coleman Mach 9 Series (RV Comfort ZC) multi-zone thermostat with the WalTech Vision 2.0. Covers the 9-pin and 2-pin connector setup with RS-485 signal wires.
Before disconnecting your old thermostat, take a clear photo of the existing wiring. This is the most important step in the process. Wire colors can vary between manufacturers and RV builders, so never rely on color alone.
The Coleman Mach 9 Series (Multi-Zone) uses two terminal blocks: one 9-pin connector and one 2-pin connector. The 9-pin handles power and heating zones, while the 2-pin carries the RS-485 communication signal.
The 9-pin connector handles power distribution and heat zone control.
| Pin # | Function | Typical Wire | Description |
|---|---|---|---|
| #1 | +12VDC IN | Solid red | Power from RV battery |
| #2 | +12VDC OUT | Red and white | Sends power to control board |
| #3 | Ground IN | Solid blue | Ground from RV chassis |
| #4 | Ground OUT | Blue and white | Ground to control board |
| #5 | Unused | - | Not connected |
| #6 | Heat Zone 1 | Varies | First heating zone relay |
| #7 | Heat Zone 2 | Varies | Second heating zone relay |
| #8 | Heat Zone 3 | Varies | Third heating zone relay |
| #9 | Heat Zone 4 | Varies | Fourth heating zone relay |
The 2-pin connector carries the RS-485 communication signal between the thermostat and the AC unit control boards. This is what enables multi-zone control.
| Pin | Function | Typical Wire | Description |
|---|---|---|---|
| 1 | RS-485 A | Purple | Communication signal A |
| 2 | RS-485 B | Black | Communication signal B |
Use the included mounting template to mark your screw locations. The WalTech Vision 2.0 uses a standard mounting plate that covers most existing thermostat footprints. If the old screw holes don't align, use the template to drill new pilot holes.
Now connect your Coleman Mach 9 Series wires to the WalTech Vision 2.0 terminal block. The WalTech uses clearly labeled pin numbers on the back of the unit.
| WalTech Pin | Connection | Coleman Mach Wires |
|---|---|---|
| Pin #8 | Ground | Both ground wires (solid blue + blue/white) |
| Pin #7 | +12V DC | Both power wires (solid red + red/white) |
| Pin #6 | +12V DC | Jumper from Pin #7 (see wire nut method below) |
Since you need to connect multiple wires to single pins, the wire nut method keeps things clean and secure.
| WalTech Pin | Function | Coleman Mach Source |
|---|---|---|
| Pin #5 | Heat 1 | Heat zone 1 wire (from old terminal #6) |
| Pin #4 | Heat 2 | Heat zone 2 wire (from old terminal #7) |
| Pin #3 | Heat 3 | Heat zone 3 wire (from old terminal #8) |
| Pin #1 | Heat 4 | Heat zone 4 wire (from old terminal #9) |
| WalTech Pin | Function | Wire |
|---|---|---|
| Pin A | RS-485 A | Purple wire (from 2-pin connector) |
| Pin B | RS-485 B | Black wire (from 2-pin connector) |
Restore 12V power to the thermostat. The WalTech Vision 2.0 display should turn on within a few seconds. If the screen does not power on, immediately disconnect power and double-check your wiring connections - especially Pin #7 (+12V) and Pin #8 (Ground).
Once the WalTech powers on, you will need to select the correct system type. Navigate to Settings > System Configuration and select:
"Coleman Mach 9 Series Multi Zone"
After selecting the system type, configure your heat stages:
| Setting | Options | Notes |
|---|---|---|
| Heat 1 | Heat Pump / Heat Strip / NA | Select the type connected to your first heat zone, or NA if unused |
| Heat 2 | Furnace / NA | Select Furnace if connected, or NA if unused |
| Heat 3 | Always NA | Not used on Coleman Mach systems |
The WalTech Vision 2.0 auto-detects which zones are active on your system. Once configured, you will see each active zone appear on the thermostat display. You can control each zone independently for cooling and heating.
If you find that the temperature reading on the WalTech doesn't match your environment, you can adjust it. Navigate to Settings > Calibration to fine-tune the temperature offset. This is useful if the thermostat is mounted near a heat source or in direct sunlight.
The WalTech Vision 2.0 auto-detects active zones once you select the Coleman Mach 9 Series Multi Zone configuration. Each zone operates independently through the RS-485 communication bus, so you can control cooling and heating for each zone from a single thermostat.
The 9-pin connector handles power (12V DC in and out), ground, and up to 4 heat zone wires. The 2-pin connector carries the RS-485 A and B signal wires used for communication between the thermostat and the AC unit control boards.
The wire nut method is recommended for the power and ground connections where you need to join multiple wires together (both incoming and outgoing power/ground wires plus the short jumper wires to the WalTech pins). Heat zone wires and signal wires connect directly to the WalTech terminal pins without wire nuts.
Multi-zone wiring with direct relay + signal based wiring.
Standard single-zone direct relay wiring guide.
All error codes for Coleman Mach, Dometic, GE, and Furrion systems.
Overview of all Coleman Mach thermostat replacements.
Our support team is here to help. Text us a photo of your thermostat and we'll confirm compatibility and walk you through installation.