Beyond the electrical work that went with the audio system upgrades, Greg pulled out the big guns to fix the heating systems in the van. Cold weather camping, here we come!
The next project was to engineer a more effective auxiliary heat system. But first, some context.
The van has two heat systems on-board:
- Residual air heat system: This system draws heat from the engine to heat the interior of the van, even while the engine is off.
- Auxiliary heater: Engages the auxiliary heater unit, auxiliary water pump, and fan to heat the interior of the van AND the engine — even while the engine is off.
The purpose of Greg’s project was to be able to heat the interior of the van and heat the engine without the key being in the Run position. Pre-heating is particularly important for a diesel engine in cold weather. How does it work? With the engine off, push the button –> water pump runs, heater turns on, fan runs. This is ideal for us since we’re planning to sleep in the van, often in cold/winter conditions.
The button for the residual air heat system was there and was working, but was ineffective because the auxiliary water pump (an electric pump that runs in concert with the other one to assist in distributing the fluid throughout the whole coolant system) was barely turning. To remedy this, he replaced the water pump. More engine work!
Then he took the switch panel out and brought it inside. Greg went to work wiring in relays that would send the signals to the proper places, even with the engine off. The van was not wired up for this prior, even though it was an option. There is a Mercedes-Benz technical bulletin that goes through this option, so Greg put his know-how to use.
Unrelated to the on-board systems, Greg is also working on a third heat source. This is a portable propane heater that he is rigging to make it safe for indoor use. It will hook directly into the on-board propane tank that will be stored on the under side of the van, similar to the way VW buses/vans are. He is planning to wire in the thermostat, giving us the ability to turn it on and off from inside the van. The particulars of this are not entirely figured out yet…
Practically speaking, if we are camping in Tahoe in the winter, we will use the propane heater to heat our living quarters overnight, then turn on the auxiliary heater in the morning to preheat the engine. Lots of options!