Almost every BMW E39 (5-series) and E38 (7-series) and E46 (3-series)
has shorts that develop in the trunk wiring loom - all in the same spot!
Here is a picture of the uniformity of the shorts:
Here is another picture from another vehicle:
I could go on (and on); but we can't figure out WHAT the BMW design flaw is.
Q: Can you tell from these pictures what the BMW design flaw is?
Not unequivocally, of course not, but it would appear likely a
temperature/time-hardening of the insulation combined w/ the flexure
point eventually fatigues in that general area.
What's the age of the vehicles and condition of insulation in the area?
Are the vehicles in very cold or hot climates and not garaged by any
chance where such degradation could have been accelerated by extremes?
Is there preferential failure in any given circuit(s)? Perhaps a
circuit operating at high capacity relative to wiring
ampacity/insulation rating is aiding in the failure mechanism.
What does BMW say?
These 3,4,5 series BMWs are some of the best handling and safest
vehicles on the planet. The M62, M62TU, M54, M52, & M52TU engines
are bulletproof, and the suspensions superb.
Yet, part of owning a bimmer is fixing it yourself. Otherwise you'll
go broke with the repairs. I know of scores who have "repaired"
their trunk wiring loom - but I don't know of any who went to the
stealer to have it replaced.
I was only answering the question of what BMW says to do.
We all work on our own vehicles so we repair them ourselves.
Cost to "repair" is about $20 give or take - but the real question
is why it breaks in the first place. It looks like, from the discussions,
a combination of poor choice is insulation plus a badly designed snorkel.
When you are paying what most BMWs cost, you pay to have it repaired. Most
often you do not keep it long enough to need repairing. They are not made to
be repaired, but traded every couple of years. It is a status symble, not
something ment to last.
While it was only a Mercury at the time, friend of mine had a good thing
going. He was friends of a car dealer. A high payed execitive would not
let his wife keep a car but 2 years. She seldom drove it. In 2 years the
car would have less than 10,000 miles on it. My friend got a great car deal
on a slightly used one. Those cars spent most of the time in a garage.
yeah, it's easy.
1. the wire coating has a poor grade of plasticizer*, so the coating
cracks and bending concentrated at the cracked coating will fatigue the
2. they're using an elbow bend, not a torsion bend. the stress
concentration at the surface of the wire coating is less with a torsion
#1 is a factor of the germans being too "green" for their own good and
not using good old toxic pvc. #2 is the real screw-up - they would know
that one if they'd spoken to anyone who'd been around the block or had
done their own testing.
* the plasticizer used in the wire coating is crucial to give it
flexibility. the basic polymer insulator extruded over the wire is very
brittle without it, so a plasticizer is added for flexibility. if the
plasticizer is too volatile and evaporates over time, the coating will
become hard and brittle per the original polymer, then crack when
bending stress exceeds a certain value.
And maybe you've found the root cause of the problem.
Instead of using decent wire suited to the application,
the Europeans chose to use some green hippie wire,
that not only costs more, but fails.....
respectfully and completely disagree on that. the stranding is
perfectly fine if the insulation remains intact. once the insulation
cracks, then you have substantial strain concentrated in just one spot.
even fine wire high count stranding will break if subject to such a
the fix is both better wire insulation that doesn't become brittle, AND
re-routing to avoid the elbow bend. then you can keep using cheap wire
and don't need to spend money on the expensive hi-flex stuff.
my wife broke the inside passenger side..
i've learned to use only two fingers to pull on the handles, don't
i agree they are not very rugged...
but it's about the only flaw i've found with that car (knock knock)
besides the rear door wires which i understand like the BMW is a very
common spot for wires to break on this car...
and interestingly the rear door is used maybe 1/100 of the time
compared to the drivers door so you would have to think there is
something "special" about the way those particular wires are designed
and/or built to make them break before the drivers door wires break
The inside handles seem to be designed to break at the 8 to 10 year
mark. The have a slot molded in to the highest stress point, I might add
I don't see any reason for it. Other than to help the dealer sell
Other than the door handles I'm a happy Toyota owner, had a Camry,
have a T-100 still a sharp looking truck, have a Lexus and an Avalon.
My wife is a persistent patient shopper, and will wait until she finds
a great used car at a steal.
Of course it can be. If BMW uses some hippie green
insulation that isn't as pliable as other insulation, then
the insulation will crack. We can't do a forensic investigation
from some pics that don't show how it's mounted, how
much it moves, what tensions are on it, etc. But I'd bet
that area has more bending, tension, etc than the rest of
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