E39 Electrical Problems Traced to Trunk Lid Harness Wire Chafing (DIY Diagnostic)

What do each of the 13 wires innervate in this E39 trunk lid wiring?

Is there a TIS on this apparently common wire-chafing problem?

The reason I ask:
- To improve our DIY procedure: Many of us have chafed or broken wires, which seem to enervate various lighting and latch components; many of us find out only because of weird trunk or lighting electrical problems; if we knew which components were innervated from this wiring harness, we could better build a DIY diagnosis of where to look for problems in the future!

EDIT: These electrical gremlins are known to be related to the trunk loom wiring harness:
- Trunk latch problems (not working, intermittent, weird behavior, etc.)
- License plate light problems (especially one and not the other)
- Trunk light problems (especially intermittent, fuse blown, or no power)
- Central Locking (ZV) system problems (of which there are many)
- Fuses blown related to the trunk latch, door locks, or tag lights

KNOWN LOOM WIRE CONNECTIONS:
01. Red/yellow line = 2 @ x712 -> trunk lid light (positive)
02. Red/black line = ?
03. Gray/yellow line = 3 @ 1377 -> tunk lid locking switch (open signal)
04. Brown/gray line = 2 @ x709 -> left license plate light (positive)
05. Gray/Brown line = 4 @ x311 -> zv drive (lid closed)
06. Gray/black line = 2 @ x710 -> right license plate light (positive)
07. Gray/Green -> 4 @ x311 -> zv drive rear lid (positive)
08. White/ Brown line = 3 @ x311 -> ZV to luggage compartment light
09. Brown = 1 @ x709 -> left license plate light (ground)
10. Brown = 1 @ x710 -> right license plate light (ground)
11. Brown = 5 @ x311 -> zv drive ground
12. Brown = 1 @ x1377 -> trunk lid locking switch (open signal)
13. Brown/blue line = ?
NOTE: (majority color[s])/(line color)=(pin number)@(connector number -> description

Originally Posted by aliaw528

My trunk lights stopped working last month, and i have always had some weird electrical gremlins. I read about this on Roadfly, check your wiring loom in the trunk where it exits out the hole. Looks like when the trunk lid is pushed to the fully open position (beyond 90 degrees), the wire loom gets cut on a deck lip because BMW made the wire loom too short. I fixed my broken wire with a connector (that was the trunk lights) wrapped each wire in elec tape, then put rubber bike tubing around that and elect taped again, then rolled the OEM boot on again. Next i need to put a rubber washer on the trunk lid deck lip. When fixing this, it is easier if you roll the rubber boot down.

1. how did you even begin to figure out that you had a problem there?

2. (work around solution) are there connectors near the ends of the harness? might be a cheaper and far reliable to buy the harness from guys parting out

Originally Posted by z168

1. how did you even begin to figure out that you had a problem there?

It wasn't easy. Neither was it efficient.

I simply had weird electrical problems over the past 6 months of ...
a. Cluster suddenly reports "CHECK LICPLATE LIGHT" ...
b. Brand new 6418 13.5 volt 5 watt bulbs didn't light up ...
c. Trunk latch weirdly starts unlatching when I move the trunk ...
d. Wiggling just the scuba hose caused the trunk to latch & unlatch ...
e. Someone with the same problem posted their experience with the loom ...
f. Another E39 owner reported a cluster OBC error for years due to the same problem ...
g. Yet another E39 owner reported fuse #37, cluster lights, tag light, & taillight out due to this problem ...
h. Yet another E39 ... and another ... and another ... and another ... and another ... and another ...
i. Here is a Bimmerforums thread on this problem in the E39 ... and Roadfly ...
j. A nice set of pictures of the problem in an E39 is here ...
k. E39 Trunk Constantly Unlatches & E39 Dash Open indicator light & E39 Wires make me crazy

It seems to have taken months or years to find the real culprit for some (including me).

If we list what is affected by these 13 wires, and which fuses can blow, then we can help many others!

2. It might be a cheaper and far reliable to buy the harness from guys parting out

I'm currently trying to figure out what the part number is for the harness.

It's either the cheaper well-named P/N 61116907260 "trunk lid harness" $215 USD + 10% tax ... or ...
It's the much more expensive poorly-named (if it's this) "trunk harness" P/N 61116936272 $1,708 USD + 10% tax (ouch)!

I'm hoping it's the cheaper two-hundred-dollar harness but I can't tell from the RealOEM diagram I posted whether it's harness #3 or harness #4.

Can someone help identify the part number & dozen items it affects?



For cross reference, other BMW models with trunk loom chafing or broken wires were:
- E34 Wiring Frayed and another and another
- E36 Boot Wiring (more E36 boot wiring) plus E36 Frayed Trunk Wiring and more E36 trunk wiring problems
- E46 Trunk Lid Wires

Originally Posted by bluebee

What do each of the 13 wires innervate in this E39 trunk lid wiring?

Is there a TIS on this apparently common wire-chafing problem?

The reason I ask:
- To improve our DIY procedure: Many of us have chafed or broken wires, which seem to enervate various lighting and latch components; many of us find out only because of weird trunk or lighting electrical problems; if we knew which components were innervated from this wiring harness, we could better build a DIY diagnosis of where to look for problems in the future!

as for the pn 03 and 04 looks like certian yr. models.
now for the color wires. i hate to tell you this. but what i would do is hook up each wire one at a time. and see what comes on. if you unplug the wires to the latch it self and the plate lights, and try to pull the harness out, will be the fates way to elimnate what is what.

also i'm thinking the same as you for what controls what.
inside release, out side release, remote release, left and rt plate lights, alarm sensor, lock/unlock. that's pretty much all i can figure out, but what to what don't know.
you'll have to like i have posted, just take it all out. sorry you got to be the ginny pig on this one.

Here is yet another blue BMW that has the problem.

Note: Notice this blue BMW has two of the same wires busted as mine; I'll bet his right license
plate light was out of power (I think that's the red/yellow wire).

honestly, the wires are going to the latch and to the plate lights. just unplugg it all, and slowly pull it all out. make sure there are on t like plastic clips that are taped to the harness that hold it to the trunk lid. just look around in there before you take it out, and as your pulling it out. once you have it fixed, and the wires back in place, i would zip tie the wires to the trunk lid. they are obiviously moveing as you open and close the trunk.



edit---doing body i can tell you this, takeing the wires out is a straight forward job. it is really easy to do. just make sure that the harness isn't tied down to the deck lid. the hardest part is making sure that you get the right wires back together. i would also recommend you takeing the latch out and the plate lights, so you can test the parts once you get the wires out, so for one you can see what does what, and you can make sure there are not problems. a tip, take a screw driver and manually latch the latch, so you can make sure it works.

In looking for the definitive DIY that pulls the harness out for repair or replacement (which I did not find) I did find this E36 DIY ... again with the same problem as we have on the E39 - and again - a BLUE BMW.

Why are only the blue-b's affected! I'm starting to feel a little superstitious ... only Blue B's have posted pictures on the Internet of the busted
trunk wires!

so are all these breaks in the wires located up and inside of the trunk lid or in the rubber hoseing?

Originally Posted by lild

so are all these breaks in the wires located up and inside of the trunk lid or in the rubber hose?

Hmmm... I didn't look before I pulled back the rubber hose. You have a good question.

Are the breaks due to the sharp edges of the trunk lid itself at the ends of the rubber hose or due to the stretching of the wires (in which case it might more often break near the centerline of the rubber hose).

Looking at the pictures again, it seems most of the breaks are in the same spot (within a couple of inches) in any one loom ... and it seems that most breaks are about a half a foot from the lid of the trunk. If it were mere fatigue bending and stretching, I'd have expected, somehow, the breaks to be centerline in the hose itself, but they seem to be further up, closer to the trunk. (Interestingly, all the pictures I've found are on Blue B's!).

What does that tell us?

don't buy a blue bimmer. lol
i thought more about it last night. these wires should be able to bend without breaking into 2, plus some are still together, but have the wire scrape back. so my thinkin is this.
the wires must be staying in place. for exp. the wires are a certian length, but they are moving in and out of the rubber hose every time you close and open the trucnk lid. so they may be contiuneouly rub the inside of the deck lid, causeing the bare wire, and then breaking.
so we could do 2 things, one make the wires longer, or two, buy some plastic wire wraps that advance sells, (sorta like the rubber hose) wrap the wires (after splicing back together) and then reinsert the new wrap wires into the rubber hose.

Originally Posted by lild

Don't buy a blue bimmer

too late!

we could do 2 things, one make the wires longer, or two, buy some plastic wire wraps that advance sells

Advance?

Is that http://www.advanceautoparts.com (877-ADV-ANCE)?

It's really really HARD to find anything on their shop-online site because they are just about the only sales web site on the planet without descriptions for their product (other than the name).

Is this what you're referring to?
Dorman Electrical - Wiring Accessories

Part No. 85266

http://shop.advanceautoparts.com/web...A|GRP2020A____

Nothing in the TIS that I can find, but I only figured out how to install it just this morning….

Originally Posted by bmw_n00b13

Nothing in the TIS that I can find, but I only figured out how to install it just this morning….

Drat! It would really be nice to have the 13 (or so) components listed which that problematic trunk loom connects to.

If we had that definitive list, we could point folks with related electrical oddities to the trunk lid wiring harness for DIY debugging.

I really wish I could find my second Bentley to see if the wiring diagrams there offer any light as to the purpose of the 13 wires!

01. Red/yellow stripe = ? (possibly right license plate light)
02. Red/black stripe = ?
03. Gray/yellow stripe = ? (possibly trunk un-latch electronics)
04. Gray/brown stripe = ?
05. Gray/brown stripe = ?
06. Gray/black stripe = ?
07. Gray/green stripe = ?
08. White/brown stripe = ?
09. Brown = ? (possibly right license plate light)
10. Brown = ?
11. Brown = ?
12. Brown = ? (possibly trunk un-latch electronics)
13. Brown/blue stripe = ? (possibly trunk un-latch electronics)

In searching for wiring diagrams on the net, at least I finally found a picture of a non-blue BMW that exhibits the problem (this picture doesn't actually show the problem but the description is apropos). Of course, it's the E36, so the problem is on the other side of the trunk; but it's the same problem (here's one where the BMW E36 almost caught on fire!).

I'm still looking for what problems to tell others to look out for. Here's one case of lights flickering as the trunk was raised and lowered (similar to my situation of trunk lock actuating as the trunk was raised and lowered).

See this enticingly short explanation of what causes the problem here ...

"The insulation starts cracking where the wire flexes - and eventually things start misbehaving."

The question is still the same: What "things" can misbehave?
- Trunk latch
- License plate light
- ??? (what else)???

.

These wires are so thin (like 22 gauge) I didn't feel comfortable with a connector. I spliced and soldered my connections and then rewrapped each wire with cloth hockey tape and then wrapped the bundle and put back the rubber hose. So far so good.

Originally Posted by bmw_n00b13

Nothing in the TIS that I can find

I find it very surprising if there isn't a technical bulletin on this, apparently common, yet perplexing problem.

In scouring the Internet for an explanation of the 13 wires, I found this excellent BMW M3 trunk lid replacement DIY.

In that M3 boot lid replacement DIY, we find out, for the first time, there are 5 connectors in the M3 trunk loom (notice the absence of a specific connector for the license plate lights):
- 2 reverse lights
- 1 locking mechanism
- 1 trunk release button & license plate lights
- 1 trunk latch

We also can deduce the BMW M3 wire loom appears to be about two yards long according to my interpretation of those pictures.

Finally, we find out what some of the actual wires innervate on the M3:
- brown (license plate lights)
- gray/brown (license plate lights)
- gray/yellow (trunk release)

So, here's our best guess for what the 13 trunk loom wires innervate:
01. Red/yellow stripe = ? (possibly right license plate light)
02. Red/black stripe = ?
03. Gray/yellow stripe = trunk latch electronics
04. Gray/brown stripe = left license plate light
05. Gray/brown stripe = ?
06. Gray/black stripe = ?
07. Gray/green stripe = ?
08. White/brown stripe = ?
09. Brown = right license plate light
10. Brown = ?
11. Brown = ?
12. Brown = ? (possibly trunk un-latch electronics)
13. Brown/blue stripe = ? (possibly trunk un-latch electronics)

It is up to us to flesh out the rest of the 13 wires in the trunk lid wiring harness loom.

In digging s'more, I found this trunk-lid related electrical-problems thread which implies additional components might be associated with the 13 wires in the trunk lid loom:

That makes the potential suspect list the following (so far).
- trunk wired cabin unlock button ?
- trunk key remote unlock switch ?
- trunk lid latch (known)
- left license plate light (known)
- right license plate light (known)
- left backup light ?
- right backup light ?
- left inside trunk light ?
- right inside trunk light ?
- trunk alarm ?
- ???

What else electrical is inside the trunk lid?

Originally Posted by bluebee

Here is the updated list of 13 things that may go haywire if/when your trunk loom wire insulation begins to crack from repeated flexing

Based on this description kindly supplied by ganesht, here's what we have so far:

01. Red/yellow stripe = 2 @ x712 -> trunk lid light (positive)
02. Red/black stripe = ?
03. Gray/yellow stripe = trunk latch electronics
04. Gray/brown stripe = 2 @ 709 -> left license plate light (positive)
05. Gray/brown stripe = 2 @ x709 -> left license plate light (positive)
06. Gray/black stripe = 2 @ x710 -> right license plate light (positive)
07. Gray/green stripe = 3 @ x1377 -> trunk lid locking switch
08. White/brown stripe = 1 @ x712 -> trunk lid light ground
09. Brown = 1 @ x709 -> left license plate light (ground)
10. Brown = 1 @ x710 -> right license plate light (ground)
11. Brown = 1 @ x1377 -> trunk lid locking switch (ground)
12. Brown = ?
13. Brown/blue stripe = ?

Can someone check to see if we're right?
And, what are the missing descriptions?

Originally Posted by bluebee

It wasn't easy. Neither was it efficient.

wow thats mighty expensive. Im guessing its an assembly harness which explains the price.

Some other brand cars have documented harness issues and would be addressed by buying the improved version. since a new harness in this case would not offer a guaranteed solution, youre better off re-doing the wiring yourself.

Originally Posted by bluebee

Based on this description kindly supplied by ganesht, here's what we have so far:
Can someone check to see if we're right?
And, what are the missing descriptions?

im going to keep updating this post: http://www.bimmerfest.com/forums/sho...1&postcount=18

Originally Posted by ganesht

im going to keep updating this post: http://www.bimmerfest.com/forums/sho...1&postcount=18

There is a good wiring diagram kindly posted by ganesht in that thread so I'll just summarize here the connections to the loom wires and problems that could be related to the loom wires.

KNOWN LOOM WIRE CONNECTIONS:
01. Red/yellow line = 2 @ x712 -> trunk lid light (positive)
02. Red/black line = ?
03. Gray/yellow line = 3 @ 1377 -> tunk lid locking switch (open signal)
04. Brown/gray line = 2 @ x709 -> left license plate light (positive)
05. Gray/Brown line = 4 @ x311 -> zv drive (lid closed)
06. Gray/black line = 2 @ x710 -> right license plate light (positive)
07. Gray/Green -> 4 @ x311 -> zv drive rear lid (positive)
08. White/ Brown line = 3 @ x311 -> ZV to luggage compartment light
09. Brown = 1 @ x709 -> left license plate light (ground)
10. Brown = 1 @ x710 -> right license plate light (ground)
11. Brown = 5 @ x311 -> zv drive ground
12. Brown = 1 @ x1377 -> trunk lid locking switch (open signal)
13. Brown/blue line = ?
NOTE: (majority color[s])/(line color)=(pin number)@(connector number -> description

PURPORTED LOOM WIRE PROBLEMS:
- Trunk latch problems (not working, intermittent, weird behavior, etc.)
- License plate light problems (especially one and not the other)
- Trunk light problems (especially intermittent, fuse blown, or no power)
- Central Locking (ZV) system problems (of which there are many)
- Fuses blown related to the trunk latch, door locks, or tag lights

Each of these main problems can have weird sub problems, e.g. for the central-locking system (which relates to almost 1/4 of the wires in the loom), some of the potential problems might be:
- Key Remote Unlock does not unlock doors
- Key Remote lock does not lock doors.
- Key Remote Trunk release DOES release trunk lid.
- Key in door does unlock first driver door, then second all doors.
- Key in door does lock all doors and set alarm.
- Central lock/unlock button inside car DOES NOT work.

Gotta go and check mine over the weekend. My theory based on all these pictures and the location is that it is a combination of chaffing and stretching due to the angle at which the wires pass through the grommet. I also think that over time the rubber grommet dries up and hardens up over time increasing the transfer of friction to the wires themselves.

For those good with a soldering iron, I would splice and solder back the sheared or broken wires, re-wrap with electrical tape and put a split wire loom or spiral around the harness (space permitting) to protect it from future damage. Also would suggest replacing the dried out grommet with a softer newer one to minimize future damage. If there is enough slack in the harness, I would also pull/push the harness about 2" so that at least an area that was not previously at the bend/chaffing area is now at the bend. My theory is that this happened over a 5-10 year period so a "new area" might take that long before the wires get worn out again. I'll report back my finding over the weekend.

Here's a link to what split loom wire harnesses look like. For this application, I'd probably go with the first one-spiral wrap, both of which you can probably find at your local Radio shack or off ebay. Split loom/spiral wraps. All you need is about 6" worth of it for this.

Hi bluebee,

I read this thread with interest!

Have you found a direct swap, i.e., a part number where you can simply buy the cables with connectors and simply do a swap?
This is better than re-splicing every single wire.