Battery drain found but not solved

[tommy2704]

hi, I have a battery drain. I have found the fuses that are causing the problem and removed them to stop the drain but cant figure out the problem.

both of these need to be removed to stop the drain.
R3 RELAY IN THE BACK  (audio unit relay)    and
FUSE 72. (1st in line, the audio/nav fuse)

I have disconnected the navigation unit, the cd changer and the stereo/computer head unit
but the drain is still there until the fuse and relay are removed.

please please any help would be great as I'm new to the x5.

many thanks in advance.

[henrym3]

That would suggest that somewhere along the wiring loom between the units and fuse some of the wires have got chafed. Or try replacing the relay, it may be faulty.

[Greydog]

I have just had this very same issue the BM54 (Radio unit) was turning its self on and off randomly even when the car was asleep causing battery drain. Unplugged the quadlock on the BM54 and no more problems with battery drain. An old friend has a scrap yard (sorry Billy Parts Recycling Centre) he had a BM54 unit on the shelf and lucky me it's been upgraded by Cartronix so all fixed now.
Try unplugging the BM54 Quadlock then put the fuse and relay back plus the CD and Nav unit and see what happens over a day or so. Mine started dropping stations then it would turn off but come back on when I pushed the power knob on the head unit, I turned it off at the head unit it then progressed to randomly turning it's self on and off draining the battery over night.
Hope this helps

[tommy2704]

right I will go out and give that a try now. thanks for the advice.

[tommy2704]

right, I disconnected the BM54 unit and still got the drain. tried with a new relay but no affect. both the relay and fuse need removing to stop the drain. what am I missing ????

[Horizon]

Does the same feed supply the diversity aerial amp in the tailgate I wonder

[tommy2704]

the dsp doesn't change the situation when disconnected so I will now try the tailgate aerial amp.

[tommy2704]

NO change. battery still draining. checked all wires but cant see anything astray.

[Horizon]

https://xoutpost.com/bmw-sav-forums/x5- ... drain.html

Maybe an alternative if you can't find the culprit

[tommy2704]

right, I'm once again going to disconnect everything in the loop and replace all fuses to see what happens.
if battery isn't draining then ill replace one by one to try again to sort the problem. cant think of what else to do.

[X5-D-Sport]

Bet you £5 this is a hedge-hog fault....
The voltage regulator for the interior blower fan.

They can fail in several ways..... the most annoying is when it appears to work perfectly, but when the vehicle is switched off & locked, this little device fails so that the mossfet goes partial short circuit to the battery.
The fault is almost invisible to locate, & the vehicle won't burst into flames because the device has a HUGE heat-sink that looks like a Hedge-Hog, hence it's slang name...

The device lives atop the gear-box tunnel against the front bulkhead.
You will never find it without looking at a you-tube clip.

You will need to remove the tunnel side trim (RHS) forward of the gear knob in the foot well - note, this clips in, but also has one or two screws too, so don't just try to pull it off.

Me thinks this will solve the issue & is a 15 minute job.

Ebay has them for between £15 & £35.
I bought a cheepy 2 yrs ago & still working fine.

Regards
Grant B

[henrym3]

so in theory then if he unplugs the hedgehog his battery drain will go away?

[X5-D-Sport]

Never tried this, but for the agro to get it out, you're better to replace it & just disconnect the battery over-night instead.

[tommy2704]

The voltage regulator for the interior blower fan is on a completely different fuse. ive already stopped the drain by removing the said fuses.

[Alan Gunn]

I am with the hedgehog theory.
Don't know if it uses the same fuse as the blower but seen this many many times.