X5 Completely Dead, Won't Start

[nikolai]

Hi all, having a bit of an issue with my 3.0 with 215,000 on it. Cold temperatures here (in the teens) - I went to start it yesterday and got absolutely nothing:

- all electronics totally disabled
- no clicking sound at all
- the only thing the happens when turning the key in the ignition is a red airbag light on the dash comes on
- no interior lights on at all or signs of life, even with the current provided when hooked to a jump car or trickle charger
- battery is ~4.5 years old, so I'm pulling it now to go have it tested
- tried both of my keys

Any thoughts on what it can be before I have this thing towed to a shop?

Thank you very much in advance! - Nick