Stripped Webasto wiring...
 

I've been having issues with my 3.0D not starting quite a lot now. I've checked that it goes to sleep, that the alternator works, and that the drain when sleeping is as it should be, but it still drains a battery within days.

Anyway, while having a nosey about, I discovered these wires have been stripped at some point in the cars life — they go to the Webasto heater.

Any ideas why?

Also, I think there's a cover missing from here too?

http://soloartist.co.uk/public/X5/webasto.jpg

Those stripped wires,seems like someone got a feed off there for something else.The rest looks like mine ,as you can see from the photo.:)

Ah, I'm just missing that black plastic cover that's below your wires.

Ok mate,hope you get your starting issue sorted.
If you give us more information,maybe we can try and guide in the right direction:)

Well... about a month after I bought it, she wouldn't start. I got a jump-start, but at the end of the day she was dead again. So I charged it up and she was fine for a few days, then dead again.

Took it to a few garages who said the battery wasn't holding the charge. They tested the alternator too. So I replaced the battery with a Bosch and all was fine...

Then about a month later it was dead again.

I thought it was due to me only driving 1.5 miles every day, as this may not be enough to replenish the charge used to start and run (with the heater and Webasto) each way as it's pretty cold in the UK a the mo.

But then a few days ago, I parked up in our underground carpark, and 2 days later it was totally dead; had to use the key to open it, then had to connect it to my running M3 for 15 mins before there was enough power for it to even crank over.

One thing I had thought though was that the car-phone (Motorola V50) is always plugged into the armrest, and never used, but possibly always on charge? So I've unplugged that to see...

Last night, I took some measurements with my multi-meter:

—no draw, engine off, 12.55v
—no draw, engine on, 13.75v
—draw (blower, lights, nav), engine on, 13.75v

I also checked what the current draw is when she's powered down:

http://www.soloartist.co.uk/public/X5/meter.jpg

Battery voltage looks fine,in fact ,the no draw engine off 12.55v is what you normally get on an x5 3.OD fully charged battery.

You now removed fuse 74,lets wait and see what that does.
Another well known problem that discharges your battery is the FSR.There are loads of post here about it...just use thye SEARCH button.

May be time to replace your battery.... At least it sounds that way

Powers1, what does fuse 74 do? Not got the car with me at the moment.

Sound like you have a bad Final Stage Resistor

Its the telephone fuse (10a):)