I've installed quite a few of the Webasto/Espar clones and haven't had any issues with them...until this pair. I'm sure it was just my time and I was due. I resolved the problem with one (a fan sensor magnet) and was able to narrow down the issue with the other to a bad control board. I made a short video about these, in the hope that it helps someone else:
I am waiting to hear from the seller, to see if I can get them to send me a new control board. They did say that if I buy a new control board, they'll reimburse me. I cannot find an exact version of this control board on ebay, though.