I have the Delta Current Control (DCC) # FK45 controller, for my single 16” Spal fan, since 2015.  Last year was the first time I had to reset the temperature setting due to setting drift.
Just saying.

RTM wrote:

Well it countries to give me trouble today. Battery was dead after breakfast. My first thought was the ignition switch was the cause. Got it jumped and it was charging great so we drove around for a while. Came home and pulled it in the garage so I could start checking for a draw on the battery. My fans run for a few seconds after you turn off the ignition. Went inside for a moment and came back outside to the garage and the fans were still on. Only way to shut them off was to disconnect the battery. If I reconnect the battery they stay off until you turn the ignition on. Then the fans come on and won't shut off.

I called Auto Cool Guy and he said to check for voltage on pin 2, ignition switch source. No voltage I removed the controller and will be sending it back for repair.

What little driving we did get to do was fun. I'll be down for a couple of weeks now. Ugh

Great work on troubleshooting the issue to find the problem.  But man, it sure seems like this is a very cogent argument for a simple shrouded engine-driven fan :-)