Below is the wiring loom layout for all our Webasto Thermo Top Evo RV and marine vehicles. Since the Webasto instructions are not very clear, we've provided a simple diagram below to show where each wire should go and what it connects to.
Important Notes:
- If you are not installing a blower box in your heater system, you can disregard the relay holder and will not need to connect the relay feeds.
- The most important part of the setup is ensuring that Figure 4 has a 12V 5A power supply for the multi-controller (this wire is red/black).
- Also, ensure that Figure 6 (the brown wire) is taped up, as it is only used for the fan relay.
You will also need to untape the yellow wire from Figure 9, which will have a connector terminal already attached. Insert this into the 4-pin black connector shown in the photo below, ensuring the yellow wire from the multi-controller matches up with the yellow wire on the main wiring loom. This yellow wire is used for communication and diagnostic signals.
All other wiring for unused options must be taped up properly to ensure they do not come into contact with each other, as this could cause the heater to malfunction.
One last note: Figure 3 shows the heater feed output of 12V, typically a green/white wire. When connected to your relay, this wire activates the relay and transfers power to your blower boxes, ensuring the blowers only operate when the heater is switched on.
