Next up was to mount the sure wire board. This is the control box that allows the system to control multiple zones including the hot water tank (as a zone) and allows for running the system off engine waste heat. Running all this wire is quite complex. I only have a single t-stat and the water tank as a zone and the engine waste heat option. Despite that, the system wiring is RATHER complex! The main salon has a high low fan switch and the aft cabin and v-berth each have a high, low, off switch. The T-stat surns them on when a demand for heat arises and the switches in each cabin allow for some control based on user preference. The 2nd photo shows the aft cabin fan switch. The v-berth fan switch is mounted on the wall above the hanging locker.