No start after snowstorm

After sitting for hours in traffic in the weekend snowstorm in the midwest my 06 Jetta has died. Saturday noticed the radiator fans cycling with the car sitting outside cold with no key in ignition or anything. It started but couldn't get out for a drive with the snow. Came back later and had a dead battery due to fans running. With battery charged now no start. Pulled fuse 24 in panel B but fans still cycle. Now no glow plug light, several dash lights at random and PRNDS tranny display flashes. I suspect moisture but don't know where to start - at ECM or fuse panel, or ??

Grounds...

Grounds didn't help

So cleaned all the grounds per Bentley - 3 behind left headlight, main between chassis and block under battery tray, main ground cable from battery, ground in cowl, ground below A pillar. With no key fans still cycle when battery is connected. With KOEO, PRNDS still flash. Cranks but no attempt to start. Other indicator lights - GP, steering wheel, battery. Eventually low oil pressure alarms. So I think ECM is alive based on that.

Pulled and inspected fuses in A and B panel - none blown. Checked continuity of fusible links.
No VCDS available.
No tach reading while cranking

Any ideas? Please and thank you.

Perhaps an engine temperature sensor has failed in such a way that it always tells the car that the engine is too hot. That could produce a situation like you describe. Although bad grounds are common, I don't think they would produce an always on fan failure mode.

Taking a guess here: radiator fan control module (part of the big fan connector)? I had my car in a minor crash, bought the entire radiator fans assembly used (fans and support), as soon as I have connected it to the car, the fans started turning. Ended up buy a cheap new aftermarket fan assembly from eBay, fixed the problem. In conclusion, the problem might be located in the fan assembly.

I disconnected the fan harness at the fan as an experiment. Same symptoms without the fan running of course.