cosmin.ardelean Posted February 4, 2015 Share Posted February 4, 2015 Hello again. I am having some trouble with two heaters. I wanted to do a gift to my good friend from UK and the perfect gift for him it's a auxialiary heater. I found on internet a Webasto auxiliary heater (not W-bus or K-bus controlled) and I bought one. The seller ensured me it can be started with +12V on Pin1. The story is complicated, in the end i received not one but 2 Webasto. When i receive the package, my worst fears came true. One heater is BMW Thermo Top Z/C, the other one is Thermo Top C from VW. Both can be started only with the car's K-bus. The seller does not answer to my calls anymore, so i'm on my own. My question: what can i do to start the webasto? A new universal control unit is out of question, since the price is already high. Do you know a good priced second hand control unit? Or do you have any advice for me? Thank you. 1 Quote Link to comment Share on other sites More sharing options...
elbekko Posted February 4, 2015 Share Posted February 4, 2015 I'm not sure where, but I recall reading somewhere that the CAN controlled units can also be started manually. Did you try what the seller said? Quote Link to comment Share on other sites More sharing options...
cosmin.ardelean Posted February 4, 2015 Author Share Posted February 4, 2015 Ofcourse. I found the Thermo Top Z wiring diagram. I wired some Webasto ThermoTop C last year and they worked perfectly. But this is not working. I found this aftermarket control unit, but the guy doesn't respond to email. Quote Link to comment Share on other sites More sharing options...
TSD Posted February 4, 2015 Share Posted February 4, 2015 It's hard to give absolute answers to this, there's a lot of different units of these (same mechanics different software) and a lot of internet legend, some undoubtedly true, a lot of it rubbish. As far as I've seen, a C should still be startable by grounding one pin, but not a Z. Easiest route is to use the Webasto 1533 Oval Timer, which should start either of them. I know it has wbus output, possibly it has grounded switch output as well, but it was provided as part of the C installation kit, and will definitely start a Z in a D3, so should be a good bet. wbus command of the heater is easy to do with a microcontroller, but obviously takes some effort if starting from zero. Mine cost sub £20 but several months of head scratching. However, not all heaters seem to be the same, I sent one of my designs to a forum member in NZ and he couldn't ever get it to work with his Z, though it starts D3 thermotop Z with no problem, based on three units that I've tried. I'd try using the webasto test software and a homemade interface first, to make sure the heaters actually work via wbus. I've got a fully working aftermarket C unit that I've never managed to get the wbus test interface going. There are a few project designs out there that will give you a headstart if you want to go that way, Try looking on the D3 owners forums? Quote Link to comment Share on other sites More sharing options...
cosmin.ardelean Posted February 9, 2015 Author Share Posted February 9, 2015 I haven't tryed on D3 forums. A few days ago tested both heaters with a universal controller from a friend. Work flawlessly both. So only the control unit is the problem. Quote Link to comment Share on other sites More sharing options...
cosmin.ardelean Posted March 3, 2015 Author Share Posted March 3, 2015 In the end, the solution was another ECU. Quote Link to comment Share on other sites More sharing options...
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