F13 640d Electrical Issues

[mrteasdale]

Hi.... newbie here.

I've owned my 640d from new (late 2012) and covered over 100K fairly trouble free miles up until some electrical problems late last year which presented as multiple system failures - brake system, restraint system, pedestrian protection, driving stabilisation, parking brake, drivetrain, power steering, AC, speedometer and odometer. The local dealership took her in and, as is customary, charged a small fortune to "diagnose" the problems, then advised that certain sensors needed replacing and that I needed a new battery. Probably fair given age and mileage. Just shy of £1,000 / $1,400!! Oh, and a "5a fuse", although no clue given as to which one and why.

I have not been out in her a great deal since, and went to escape (lockdown) for a drive last week, only to find that the new battery was totally flat. Tried jump starting and failed multiple times. What little charge I was able to get in to her presented as having the same multiple system failures. In other words, dealership has failed to correctly diagnose and fix in my opinion. Dealership refused to come and collect (nice), so I set about trying to figure it out myself. Located a blown 5a fuse no. 2 in the glove box. Replaced that, charged the battery, and faults seemed to have cleared. For now!

My questions are:

In trying to determine the presence of a parasitic drain on the battery, I disconnected the negative terminal in order to measure current. This causes an alarm to sound until reconnected or ammeter inserted. Is this normal?

I was able to get my dealership to disclose "normal" current drain parameters on an idle and locked vehicle as being 40mA. When doors closed and locked, my vehicle initially draws around 12A, then 10A, then 5A, and so on, and takes around 30 minutes to eventually settle at around 95-100mA, then drops to approx. 70mA overnight. Presume this is wrong?

I often get the message "Increased battery discharge when stationary. Electrical consumers were temporarily switched off" both prior to electrical problems last year, and still now, with new battery and after expensive diagnostics and "repair"! Does anyone know what might be causing this?

My passenger side door comfort access has not worked for some time, so comfort access and comfort (touch) locking is only available on the drivers side. Which for the most part is fine really given the astronomical cost quoted to repair that! My question here is, could this failure be draining the battery?

Appreciate any words of wisdom and advice that can be offered. Thanks in advance!

[Mnfamilyguy2020]

The comfort access could be the problem, it was my neighbor's comfort access door handle and it would drain the battery every night.

There are several mentions online of this very issue. Search: comfort access BMW battery drain

Best!

[hugo_nz]

Another drain could come from a worn tracking system (if fitted) battery.

[mrteasdale]

Thanks for the advice. I'll certainly look in to that further.

Would you know if there's an easy way to access all of the glove compartment fuses? These are a pain!