With the removal of the engine, we remove the source of heat for the car and need some other way to supply cabin heat (or go cold). One option is to replace the heater core with an electric one, the problem is, this requires the whole dashboard to come out to remove and replace, not something I want to do. Enter the electric water heater from a Mitsubishi Outlander. This fairly small unit is CAN bus controlled and is reported as a 4KW heater. The problem was no one had worked out the messages required to control it, or if they had, they'd not published them. I had to spend hours and hours with this, trying to get a log from a working Outlander and working out the messages required to turn it on. The lightbulb was used as a visual indicator that the heater was working, using rectified mains as a power source, along with 12v to power the logic board. After a bit of coding and prototyping heres an Ardunio sketch to control it: https://github.com/jamiejones85/OutlanderHeaterControl
My blog covering a budget conversion of a VW Beetle to electric power, using parts from salvage.