GEOFF
Yes that is a water heater not air heater, I have one under passenger headlight. It can preheat the engine if it is wired todo so otherwise it reduces the time the engine takes to warm up. Mine has a heat exchanger and blower set up in the rear of the van so I can heat van while engine is running. The water heaters usually only work when the engine is running/ignition turned on but can be wired to work independently
My Ducato has a Webasto 5kw water heater wired as engine running. I have been on to both Fiat and Webasto, but cannot get any info about how to re wire it as a night heater. Any help if anyone knows would be very helpful. Thanks. Geoff.