No fan on auto, but defrost works
 

So is it the FSR. I know the blower works and the controls manually when in defrost mode. If not in defrost mode, I got no fan, and controls do didly.

Did ISTA-D show any code?.
You can try to run this test plan on ISTA-D to test the blower functioning.

Vehicle management--->troubleshooting--->Function structure--->Body-->Heating and air conditioning functions--->IHKA Blower--->Blower setting

Haven't run Rheingold yet. It was -21C at the cottage this morning and the car was sitting outside. Car started, but considering I am on the original AGM battery, it wasn't happy. I think the cold did the battery in too, when I stopped for gas, I lost my date.

I got home an put the charger on the battery, will run Rheingold when the battery is charged. Most likely I will replace the battery this week.

Did the HVAC blower never turn on...or did it not come on in the beginning when the engine was cold?

I ask...because the e70 is probably like the last generation BMWs (e38/e39/e46/e53) that has a cold start arrest feature that will not blow cold air on the passengers...the IHKA control panel will not blow air through the dash (and I believe floor) vents until operating temps have risen to a specific degree where the air blown into the cabin is warm.

Never came on, unless I set the controls to defrost. The blower works fine in that mode, so I am thinking final stage resistor? I'll run Rheingold tomorrow. Too cold today. I've had the X5 for seven years, battery was replaced in the first year of ownership under warranty (defective), and this will be the second. I'm at 171k km (about 105k miles).

So after charging the battery, the blower works normally again. The X5 is so prone to general wierdness when you have a faulty battery its unreal.

Battery load tester indicates it needs replacing, so hopefully I don't have another adventure with the FRM when I replace it :D

It's not weirdness, but known feature: defrost is crucial for safety; occupants comfort is not. Why? Ask BMW...

When the battery SOC is becomes critical the DME/DDE needs to maintain the battery to try and assure startability. Certain large amperage IHKA consumers are then shut off or reduced.

I knew about certain functions being disabled, (comfort access and heated mirrors etc), but I didn't know full IHKA. I should poke around in Rheingold more

Replaced the battery today, all good. I didn't fry the FRM. Even though I have an '09 and the MY 10-13 is covered for the FRM3, I'm running an FRM3 to power the halos on my LCI headlights, so I was a little bit apprehensive. I don't have the time to mess with tool32 or an eprom reader/writer to reflash the FRM.

I just kept power to it via the terminals under the hood, removed the bad battery, and replaced it, and then removed the power from the terminals