My X5 doesn't start in the morning with fuse #98 left in overnight. Sorry if this next bit is overexplained, but I'm new to this whole forum thing. Still figuring it out.
Last week I bought my first BMW: 2010 X5 (E70) xDrive35d with just under 90k miles. This is my first used car I've owned as an adult, and I have virtually no experience with car repairs, nor any interest in writing my local mechanic into my nonexistent will.
The dealer replaced the battery after the mechanic that checked it out pulled these codes:
3EED | Power Management Closed Circuit Current Violation
4A56 | Power Management Battery
4661 | Power Supply
4121 | Engine ECU Main Relay
Supposedly the new battery would fix everything (did I get swindled there?) so I bought it.
Parked overnight in my garage, it would be dead every morning (totally dead, needing 15+ minutes hooked up to jumper cables to charge). After delving into the DIY auto repair world for the first time (thanks guys, good to be here), I guessed I was dealing with parasitic draw, and proceeded to test the voltage drop across each fuse in the fuse box.
While there (with the car off/sleeping) the rear A/C fan started blowing...actually (after further investigation) sucking--like a terrible vacuum with hardly any suction. The car was still 'asleep' with no lights anywhere (shifter, start/stop button, doors, etc.). I rechecked the fuses and #98 was passing ~13v, whereas it was at 0v before the fan turned on. *bingo* = my battery draw, right?
So I've pulled fuse #98 and the rear fan no longer works (as expected). Everything else seems to work fine, so I'm planning on leaving it out until I can do so without killing my battery overnight.
But that begs the question: why is the blower turning on randomly while the car is asleep? And further: why does it spin in reverse, creating suction instead of blowing?
So far I've witnessed the phenomenon twice: once about 5 minutes after sleep, and another time about 25 minutes after sleep. Both times the fan sounded like it was at full blast, making the center console vibrate, but not blowing any air and generating a tiny bit of suction.
A few times, after I'd connect the jumper cables and charge the battery a bit, the blower would turn on along with a few other lights (e.g. the shifter, start/stop button, etc.), but I thought it was just normal after a dead battery--maybe not so.
Closest thing I can find is a
possible bad rear blower motor, but there's not enough detail here to be sure. Especially since mine is starting up while the car is OFF, not while driving. Additionally, the rear climate control works great when the car is running.
Any help to diagnose this would be much appreciated. Assuming the battery doesn't die again tonight, my next step would be to order a new blower motor on eBay and DIY install it, then re-insert fuse #98 and take a nap in the back seat hoping not to be woken up by a rude fan.
In case anyone else is experiencing something similar, here are the key resources I've used:
E70 Battery Access:
https://www.youtube.com/watch?v=bE22LoDpIQE&t
How to test with multimeter:
https://www.youtube.com/watch?v=COJr7OB23Hw
E70 Fuse Box Access:
https://www.youtube.com/watch?v=6TcGl_YJYps
Best way to test for parasitic draw:
https://www.youtube.com/watch?v=lRcj1fQcWwU&t
E70 Fuse Box layout key:
https://fusesdiagram.com/bmw/fuses-a...mw-x5-e70.html