Egg hunt completed.

Problem remains.

I found the controller and I did confirm that the controller has power from the fuse box. I also could see some grounds appear and disappear on certain pins when the high or low fan switch was pressed. No amount of fiddling would get the blower to work.

Now, here is where it gets interesting.

I had purchased a complete heater box assembly with all actuators from Houston European. Got such a good deal that I couldn't pass it up. Low and behold, it has the controller attached. So, I figure I'm all set.

I swap controllers and nothing.

The second controller does the exact same thing as the first.

So, what's the chance that I have two bad controllers?

I have a suspicion that something else is the problem, but without a schematic of that controller, I've got no way to check it.

Anyone find any schematic of all those pins. The online manual only shows the 12V input.

I might just see if I can swap these two controllers into a known vehicle. They might fit the SDL. But, it will have to wait a couple of weeks since I'll be away.