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Young Thrash Driver

E39 airbag issue

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My 03 E39 touring has the airbag light on. When the car is started it completes it's airbag self check for a fraction of a second and then the airbag light illuminates again. It has been scanned and confirmed the fault is coming from the right rear passenger door airbag area, although the airbag itself communicates it is ok. I pulled the doorcard yesterday to see what I can see, and the wiring loom (two wires, twisted together, leading from the clip that connects the airbag, back into the loom) is damaged. Some of the insulation has been torn away exposing the copper on both wires although not in a place where either wire can short circuit. A few of the copper strands that make up the wire have been separated too.

Does anybody with experience with such think this damage is enough to cause the airbag fault or cause it to fail it's self check?

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Hi Colin how much of the wire is damaged, strains broken etc? Believe when the self check is carried out a certain resistance measurement is required to balance the system . A little like the light check carried out by the e39  wrong resistance measured and a warning light shows.Their are a number of items on the net about this problem water soaked loom from sun roof etc. Repair the damaged wire, heat shrink the repair scan it again to see what happens.

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Can't you just disable and physically remove the rear airbags here? In the US and other countries, we disable those when child seats are installed anyway...

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7 hours ago, allan said:

Hi Colin how much of the wire is damaged, strains broken etc? Believe when the self check is carried out a certain resistance measurement is required to balance the system . A little like the light check carried out by the e39  wrong resistance measured and a warning light shows.Their are a number of items on the net about this problem water soaked loom from sun roof etc. Repair the damaged wire, heat shrink the repair scan it again to see what happens.

Thought it would be something along these lines. The damage is really quite superficial, one wire is just missing some of the insulation and the other is missing maybe 10mm total insulation and 5 strands broken. Any ideas what would be the best way to repair this kind of important safety feature (from a legal and VTNZ view), cut and solder or some kind of specific connector?

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9 hours ago, Young Thrash Driver said:

Thought it would be something along these lines. The damage is really quite superficial, one wire is just missing some of the insulation and the other is missing maybe 10mm total insulation and 5 strands broken. Any ideas what would be the best way to repair this kind of important safety feature (from a legal and VTNZ view), cut and solder or some kind of specific connector?

Got to wonder what an entire unit from a donor car would cost? Or is the loom not just isolated to the door? 

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These wires are from memory no heavy weight so even that small number could course some difference. Would definitely repair/ replace the broken strands of wire even that small number could up set things. Not keen on cutting and using connectors in this case could create more trouble

Personnel I would begin by laying and twisting the broken wires back together then soldier them in place cover it, heat shrink an test. If not to involved could that section of wiring in the door be replaced.  Also do some research and try and find some tech details on what sort of values are required to stop the light from coming on. Pain in the rear but best of luck.

 

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The door loom is separate from the main loom, so you can source just the inner-door wiring for the airbag (or a whole door loom).

May be a better option if you're not 100% confident with splicing in new wiring.

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You need to sort out whatever caused the issue to begin with before you rush to repair or replace the loom, no point fixing it all if it's just going to happen again. 

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my guess is a gorilla at some stage in the cars life re-installed the door card after a regulator repair and the airbag wire got damaged.

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You can legally remove any airbags more than 12 years old if I recall correctly. Needs a cert and warning sticker on the airbag cover however.

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My understanding is 15 yrs to be able to remove. BUT EVERY part of the system needs removal & yes certed with an ugly sticker plastered on the dash notifying of such.

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So because I hate coming across threads that have no conclusion: While the wiring to the door airbags is indeed damaged there was no actual fault (apart from an old "ghost" code) with them. After chasing codes that went from weird to outright spurious- culminating in "Passenger seatback not locking", a code that belongs on a convertible!- Tauranga Auto Electric found the whole mess was caused by a failed passenger occupancy sensor mat .

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