After experiencing some issues with our Espar /Eberspaecher D2 sprinter heater when camping in the cold at high altitude (aka, the time you really want your heater to work), we decided to add the high altitude kit to our Espar heater. Like the heater itself, we ordered it from HeatSo.com. And again shipping was fast and the price was good.
The altitude kit is really pretty simple. Its just a little box that you insert in-between the heater wiring and your heater controller (in our case, the EasyStart Timer). So it goes like this…
Original Wiring/Device Order:
Heater Wiring –> <10 pin connector> <– EasyStart Timer Controller
New Wiring/Device Order:
Heater Wiring –> <4 pin connector> <– High Altitude Sensor –> <10 pin connector> <– EasyStart Timer Controller
Wiring the high altitude kit is also pretty easy, presuming you are doing it this way for the first time. IF you are like us and retrofitting the high altitude kit, it is a much bigger pain (read: just get the high altitude kit the first time and avoid this problem). The issue is with the connectors, they are pretty easy to assembly, crimping the wires into the pins and then sliding the pins into the plastic housing. The problem is, you cant get those pins out again. Like really, not possible – I tried for about an hour and ended up destroying the plastic housing / harness.
Fortunately, if you are reading this and going through this nightmare, I have already figured it out for you. You just need to order a new molex type connector and pins. I got mine from Digikey for under $10 (but requiring about 2 hours of research to find the right part). The part numbers are WM4772-ND for the connector and WM3112CT-ND for the pins. Once you have those parts its easy. Just cut off the old connector and wire in the new one on the other side of the High Altitude Sensor.
Since the circuit diagrams from Espar / Eberspacher are hard to read (at least I don’t find them very straightforward) I put together my own wiring diagram to help me clarify things. Hopefully this is helpful to you.
High Altitude sensor wired up. The 4-pin connector came pre-wired. The 10-pin connector has to be wired up with the red, blue-white and brown wires as shown. 10-pin male connector required in order to connect to the EasyStart Timer (comes with the install kit). Wired with red, blue-white and brown wires Showing (from left to right): Heater Wiring (disappearing into dash); 4 pin connectors; High Altitude Sensor Module; 10 pin connectors; EasyStart Timer Controller (not shown) Showing (from left to right): Heater Wiring; 4 pin connectors; High Altitude Sensor Module; 10 pin connectors; EasyStart Timer Controller The male side of the 4-pin connector (that comes with the high altitude kit) mut be wired to red, blue-white and brown, as shown. Note: gray-red and brown-white wires are still wired together, per original heater post.
Note: I had the yellow wire connected through the high altitude sensor initially, this appears to be incorrect. The heater was working, but I was getting occasional ‘no signal’ errors. Will report back once this new wiring has been tested out more significantly. However, per the wiring diagram to the right, DO NOT CONNECT THE YELLOW WIRE.
Note 2: I don’t think the yellow wire had anything to do with the ‘no signal’ errors. But it is still not necessary to attach this.The ‘no signal’ problem kept on being an issue and was finally rectified by replacing the EasyStart Timer with a regular EasyStart controller. It was a long and winding road to get to that conclusion which you can read about here.