Home / Support / Installation / Dometic & GE 3-Wire

Dometic & GE 3-Wire Wiring Guide

Signal-based single-zone thermostat replacement. Power, ground, and one communication wire - that's all you need.

Overview

Dometic and GE single-zone thermostats use a 3-wire system: 2 power wires and 1 communication/signal wire. Unlike relay-based systems (such as Coleman Mach), these thermostats communicate digitally with the control board. The WalTech Vision 2.0 speaks the same protocol - so you simply connect the three wires and configure your system type.

Before you begin: Turn off all power to your RV HVAC system at the breaker or disconnect. Take a photo of your existing wiring before removing anything.

3-Wire Identification

Your Dometic or GE thermostat has 3 wires coming from the wall. Here is what each wire does:

Label Wire Color Function
R Red +12V DC Power
G Green Ground (-12V DC)
W White Signal / Communication Wire

3-wire layout (left to right): Ground (left) - Signal (middle) - Power (right)

1 Identify Your Wiring

Before removing your old thermostat, take a clear photo of the wiring connections. This will be your reference if you need to double-check anything during installation.

Confirm you have exactly 3 wires: one red, one green, and one white. If you see more wires or an RJ11 telephone-style cable, you may have a Dometic CCC multi-zone system instead - check the Dometic CCC guide.

2 Mount the WalTech Vision 2.0

Use the included mounting template to mark your screw holes. The WalTech Vision 2.0 uses a standard mounting plate that fits most existing thermostat locations. If your old thermostat used a different screw pattern, you may need to drill new holes.

Secure the mounting plate to the wall first, then route your wires through the opening before snapping the thermostat onto the plate.

3 Connect the Wires to WalTech

Connect each wire to the corresponding pin on the WalTech Vision 2.0:

WalTech Pin Wire Connection
Pin #8 Green wire Ground (-12V DC)
Pin #7 Red wire Power (+12V DC)
Pin #11 White wire Communication / Signal wire (right side connector)

No jumper wire is needed for Dometic and GE 3-wire systems. These are signal-based systems, not relay-based - so the WalTech communicates digitally with your control board rather than switching relays.

Stability tip: Connect a short jumper wire from Pin #8 (Ground) to Pin #16. This provides additional grounding stability and helps prevent intermittent communication issues.

4 Power On

Turn the power back on at the breaker or reconnect your RV power source. The WalTech Vision 2.0 should boot up and display the setup wizard within a few seconds. If the screen does not turn on, double-check your power and ground connections at Pin #7 and Pin #8.

5 Configure Your System

The setup wizard will ask you to select your thermostat brand and system type. Configuration differs slightly between Dometic and GE.

Dometic Configuration

Select the option that matches your specific Dometic system:

  • Dometic with AC + Furnace Only - Most common setup. Single AC unit with a gas furnace.
  • Dometic with AC + Heat Pump + Furnace - AC unit with both heat pump and furnace for heating.
  • Dometic with AC + Heat Strip + Furnace - AC unit with electric heat strip and gas furnace.

GE Configuration

GE systems are more flexible with heat staging. You can customize each stage:

  • Stage 1 Heat - Set to Heat Pump (if your system has one)
  • Stage 2 Heat - Set to Furnace
  • Leave unused stages as NA
Furnace-only systems: If you only have a furnace, set it as Stage 1 and leave all other stages as NA. There is no need to configure stages you do not have.

Error Codes

Dometic Error Codes

Code Meaning What to Check
E1 Communication Loss Check white signal wire at Pin #11. Verify connections are tight.
E2 Freeze sensor temp out of order Freeze protection sensor on the evaporator may be disconnected or faulty.
E3 Outdoor sensor temp out of order Outdoor temperature sensor may be disconnected or faulty.

GE Fault Codes

Code Meaning
F1 Indoor temperature sensor fault
F2 Outdoor temperature sensor fault
F3 Evaporator temperature sensor fault
F4 Communication error with control board
F5 High pressure switch triggered
F6 Low voltage detected

Frequently Asked Questions

Do I need a jumper wire for a Dometic or GE 3-wire system?

No jumper wire is required because these are signal-based systems, not relay-based. However, we recommend connecting a short jumper from Pin #8 (Ground) to Pin #16 for added stability.

What is the difference between Dometic and GE configuration?

Dometic requires you to select your exact system type (AC + Furnace Only, AC + Heat Pump + Furnace, or AC + Heat Strip + Furnace). GE is more flexible - you can assign each heat stage individually and leave unused stages as NA.

My screen turns on but I get an E1 error. What should I do?

E1 means communication loss. Check that the white signal wire is securely connected to Pin #11. Also verify the ground wire at Pin #8 is tight. If the issue persists, try adding the jumper from Pin #8 to Pin #16.

Still need help?

Our support team is here to help. Text us a photo of your thermostat and we'll confirm compatibility and walk you through installation.