Step-by-step wiring guide for replacing your Coleman Mach 8 Series (RV Comfort ZC) multi-zone thermostat with the WalTech Vision 2.0. Uses a single 9-pin connector with direct relay and signal-based wiring.
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 8 Series (Multi-Zone) uses a single 9-pin connector terminal block. Unlike the 9 Series, there is no separate 2-pin connector. Instead, the 8 Series uses a single signal wire for communication.
The 9-pin connector handles power distribution, heat zone control, and includes the signal wire terminal.
| 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 | Signal | Purple | Communication signal to AC unit |
| #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 Coleman Mach 8 Series uses a single signal wire instead of the dual RS-485 wires found on the 9 Series. This purple wire comes from terminal #5 on the old thermostat and handles all communication between the thermostat and the AC unit control board.
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 8 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) |
This is the key difference from the 9 Series. The 8 Series uses a single signal wire that connects to the right side connector of the WalTech Vision 2.0.
| WalTech Pin | Function | Wire |
|---|---|---|
| Pin A (right side / Pin #15) | Signal | Purple wire (from old terminal #5) |
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 8 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 main difference is the signal wiring. The 8 Series uses a single signal wire (purple) that connects to Pin A on the WalTech right side connector (Pin #15). The 9 Series uses dual RS-485 signal wires (purple and black) via a separate 2-pin connector that connect to Pin A and Pin B on the left side. The power, ground, and heat zone wiring is identical between both series.
The single purple signal wire from terminal #5 on the old thermostat connects to Pin A on the right side connector of the WalTech Vision 2.0 (Pin #15). This is different from the 9 Series, which uses the standard Pin A and Pin B on the left side connector. Make sure you use the right side connector or communication will not work.
Yes, that is completely normal. Many RVs only use 1 or 2 heat zones even though the Coleman Mach 8 Series supports up to 4. Leave unused heat pins empty on the WalTech. The thermostat will auto-detect which zones are active during configuration.
Multi-zone wiring with RS-485 dual signal wires.
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.