02-05-2013, 08:30 PM
Seek to understand,^Value
Location: San Jose, California
Join Date: Mar 2008
Mein Auto: 02 BMW 525i M54 automatic
I wish I had done the parasitic drain test when things were working OK, so that I'd know what the nominal quiescent values are for my bimmer - because 90ma seems about double what it should be - but - as noted, it's not all that bad.
Originally Posted by mbell666
PS 90ma is a little on high side but not that it should cause a problem. I believe it should be around 45ma.
The good news is that I think I'm getting closer to the culprit. The problem appears to be intermittent, so the longer I spend diagnosing, the more I am learning.
For example, see this 30-second video taken a little while ago when I returned from an errand and started checking the parasitic drain again.
All of a sudden, the active current began fluctuating between 2.27 amps and 11.53 amps!
Here are those same clicking sounds, about every 3 seconds, taken from the cockpit just after the video above (they seem to be coming from behind the MID but I can't really be sure).
Notice the audible clicks coming from the front of the car, behind the dash somewhere, where each time you hear a click, the quiescent current jumps from about 2.27 amps to about 11.53 amps!
In that 30-second video, the current fluctuates at about 3 second intervals from:
The fluctuating current is different depending on whether the bimmer is in the initial active phase (first 16 minutes) or in the quiescent (computers off) phase (after 16 minutes); but here are two back-to-back photos taken of the current fluctuation when the clicks were heard:
- 2.27 amps
- 11.53 amps
- 2.27 amps
- 11.18 amps
- 2.27 amps
- 11.35 amps
- 2.27 amps
- 11.10 amps
Note: I was getting worried about my 10 amp meter because the current was as high as 14 amps during these regular click cycles.
To further debug:
Here is a picture of the FSU in situ:
- I moved the passenger seat aft & lowered the back as far as it would go
- I disconnected the battery (so that sparks wouldn't fly)
- I removed the underglovebox panel (breaking the white tabs in the process)
- I located the FSU in the tunnel but decided to remove the fuse instead since I have never done that before.
- I desperately tried to disconnect the three harness connectors in the way
- These diabolical things could foil Houdini!
- How on earth does that big one disconnect?
(If we could disconnect it - we'd have an easier time with the two fuses!)
Since I couldn't remove the three harness connectors for the life of me:
- I pushed up the closest (furthest aft) F76 yellow fuse with a screwdriver
And, then I reconnected the battery to test for parasitic drain.
- First 16 minutes: Active current = 1.89 amps
- After 16 minutes: Quiescent current = 80 milliamps
In summary, the parasitic current data is hugely inconsistent depending on whether the "clicking" sound is heard.
However, I'm pretty sure the intermittent huge fluctuating parasitic current is due to the ACM FSU I bought in 2/2/2009 going bad.
With the fuse F76 removed, I'll keep an eye on the parasitics for a few days - but the evidence seems to implicate the aftermarket ACM FSU.
Meanwhile, since I KNOW it will be difficult to get F76 back in, does anyone know HOW to get those three harness connectors off (especially the largest one, which would make access muuuuch easier when removed)?
The connector seemed similar to that of the ABS control module connector, in that there is a u-shaped slider - but I could only move it so much - and then nothing else moved.
A video of someone smart enough to remove that connector would be a blessing to see!
Last edited by bluebee; 02-05-2013 at 09:51 PM.
Reason: Added detail.