Attention: ALL E36 owners beware - WIRING PROBLEM

[vaderTT76]

I checked mine last week and found this.

29mkbrq.jpg

[RN WC]

Dang. Wish I had seen this thread last week. Dash lights and right rear and front running lights stopped working on my son's 328i. Eventually found the frayed wires in the trunk harness.

PS sometimes the "Z" shaped conductor used in some plugin fuses can be blown but look just fine. Apparently they sometimes blow just outside the window where you can't see it. Its a good idea to swap in a fresh one even if the fuse for the circuit looks OK.

PSS - Anyone need a brand new E36 headlight switch?

[DaRvDrUmS]

Wait, just to make sure, this problem wouldn't apply to a 318ti hatchback would it? lol

[Chapel]

How much is the repair cable lately?
Could I just splice all new wires in? would that be easier? cheaper for sure, yeah?

[CMG]

You don't need new wires unlessed they burn up. If so u should get tha matching wire from junkyard to solice in.

[PaulE36]

Would this be the cause that on occasion my control says "brake light circuit failure"... sometimes it goes on, sometimes it doesn't or sometimes it's on and then will just go off randomly?

[RN WC]

Would this be the cause that on occasion my control says "brake light circuit failure"... sometimes it goes on, sometimes it doesn't or sometimes it's on and then will just go off randomly?

It's easy enough to check. Just open the truck and find the bundle of wires that go into the trunk lid on the left side. Roll/pull the rubber sleeve down from the top until you can see the point where the wires bend when the truck lid is closed. If you have frayed, broken, or exposed wires there you should repair them.

[EE05063]

Checked my 97 M3 Sedan the other day, wires are perfect. There was an extra piece of grey rubber wrapped around the wires in that spot where it bends.

[joey1214]

My automatic interior lights, windows, sunroof and central locking all went out together and the number 7 fuse kept blowing. Sure enough after checking my trunk lid harness I discovered 3 of 10 wires with no insulation left. After I fixed it everything works perfect again. Thanks for this thread guys.

Joey

[Danni540]

I have two sedans and I swapped the trunk lids between them recently. Wires were like new.


Had to fix the whole wiring loom to the trunk on my E34 though, they're worse than the E36 when it comes to trunk wiring.

[EE05063]

I have two sedans and I swapped the trunk lids between them recently. Wires were like new.


Had to fix the whole wiring loom to the trunk on my E34 though, they're worse than the E36 when it comes to trunk wiring.

My sedan was like new too, it also had an extra piece of rubber at that specific location. Makes me think they found a fix and implemented it later during production since sedans didn't start until 9-96.

[johnf]

When I preemptively replaced my trunk wiring, I removed the upper, grey vinyl(?) chassis feed through tube because it made the wire bending radius even more insufficient. From my experiments increasing the radius, I reckon the tube insures the cable won't rub against the trunk wall.

[Cheeseburger]

1997 E36 328i... poking around to see why the boot/trunk light isn't working:



- - - Updated - - -

So what is the solution to stop this happening again? I'm thinking about repairing with glue-lined heat shrink, but this spot obviously needs a repair method capable of kinking... or is the introduction of rigidity exactly that the loom needs at that point?

Is there an 'ultimate' fix?

[johnf]

Your picture is consistent with too small a bending radius. I did all that I could to increase the ratio of the bending radius to the wire diameter. Specifically, I:

• removed the stiff, trunk lid panel feed-through tube that kinks the wires
• replaced all the wiring from inside the trunk to inside the trunk lid with thinner walled, wide temperature range, long life Tefzel (ETFE) aircraft wire, and
• lengthened the flexed section by clipping the lower end to further down the trunk lid hinge.

The following two pictures show the changes:





In the second picture, note the arc of the thinner wire bundle, and the extra wrinkly, black sheath.

[gc325is]

I have noticed how the wires groups are straight on all the posted broken wires. This may be a Hint to why some cars have fail wire sets and some do not.

A bundle of 9 straight wires CANNOT bend easily because the outside wire needs to travel longer than the inside wires, this will cause stress within the wires and insulation. However a simple task of twisting the wire set a few rotation per foot creates situation where all the wire travels more or less the same distance and the bundle will easily bend. This is how stranded wires are constructed.

Attached is my trunk wires and note how there is a TWIST in the wire set and so far no broken wires.

Attached Thumbnails

[Bmwdiseez]

I had same problem with my 95 325i it kept blowing fuses and trunk light would stay on, opened up the wire sheath and the pretty much all broke in my hand. Glad I caught it before fire.

[ultimatetester]

My sedan was like new too, it also had an extra piece of rubber at that specific location. Makes me think they found a fix and implemented it later during production since sedans didn't start until 9-96.

Today I found out my wires are broken too. I have a European E36 sedan from '96. I did see the rubber you are speaking of, but the broken wires were more downwards, had to pull away the rubber at my best to see the broken wires.
Here's a pic of them, and you can also see the rubber that's probably meant for reinforcement.



Mate I swear I can't get these images to be smaller. Normally I would expect that resize icon to show up but it doesn't for some reason. If mod sees this, pls resize thank you.

[ZeBimmer325is]

So, I'm having a problem with the #33 fuse, Which is my e36 325is 95, Left rear, front running Lights and the interior, Trunk, glove lights...
So, I replaced the fuse with a 10 amp as required and it blew the fuse, so I went back to the trunk with the information from this forum, which I really appreciate,
and Found 4 damaged wires on the harness in the number 1 area. I masked each wire with electrical tape and hoped for the best, replaced the fuse and chhaaaaaak
it blew the fuse. Help!! If I could get some "in-lighting" advice to what seems to be the problem here i would really appreciate it, It would benefit us E36ers. I'm going to give the area "2" a second look with Photos and hopefully find the culprit. Thanks for your time if you have read this. wish you the best.

[weedshoes]

I'm having the same issue

[patrickjam3s]

Make sure you are inspecting the wires inside of the trunk lid as well not just where they come out of the lid and run to the body, they could have frays from rubbing the lid/and/or/body from closing and opening the trunk,

If all the wires are dandy there check the fuse box for any corrosion that is causing a short shouldn't be anything there usually isn't, a volt meter and a light tester will be your best friend if it's not in the trunk wiring, get a PDF copy of the e36 Bentley wiring manual, if you can't find it I have a copy on a HDD somewhere I can email to you guys just let me know

The wiring manual will help with tracing wires and seeing where they run in the car

Hope this helps

[LumpyE36]

My car had a massive draw when I bought it. Reading this thread led me to check my trunk harness hoping it would solve my electrical problems. After cutting it open I saw it was in really bad shape.







Two people had been here to fix it before. One did a good job, one did a pretty shitty job




Cut out the bad



Solder and shrink wrap in some good...



Some electrical tape and call it a day. Didn't end up fixing my draw, but my locks work better now, don't have to lock 'em twice. My draw ended up being a previously flooded ECU. This is a problem with pre-94 E36s if you're having problems...

[patrickjam3s]

Also check the wires that run from the unibody into your doors they can fray too this would be somewhere to check if say your locks aren't working right

[Tomas328]

I went and checked mine and it is double wrapped, looks good, thank you for this thread

[simonmt]

Hi guys newbie from the UK with a 323i Coupe suffering the blowing fuse issue which I will now check tomorrow, looking forward to that one lol
My main question though is that is it possible that this can cause the battery to drain on the car overnight?

[1215]

Hi guys newbie from the UK with a 323i Coupe suffering the blowing fuse issue which I will now check tomorrow, looking forward to that one lol
My main question though is that is it possible that this can cause the battery to drain on the car overnight?

That's a vague question. You could have a bad battery. Have you had it tested? What fuses are you blowing?

It cannot hurt to check the wires going to the boot lid as it is a well documented issue with this car.