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: And another: And another: And another: And another: 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?

> > > > > 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 wire. 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 bend. #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.

What is the root of this BMW design flaw in all 3,5,7 series BMW trunk wiring looms?

Mar 14, 2013 103 Replies

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dizzy 13 years ago

This "Jim Beam" is a real stupid troll.

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R. Mark Clayton 13 years ago

Well it is nearly fifty years, but IIRC Mini's won the Monte Carlo Rally many times (and would have come 1, 2, 3 in 1966 if they hadn't fudged the rules to disqualify the Brits and let a French car win...)

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jim beam 13 years ago

people that talk smack about fwd vehicles don't know how to drive them.

regardez:

and from 1991 onwards:

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dizzy 13 years ago

Stupid.

There's not a purpose-built race car on the planet that is FWD. There are reasons for that.

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