I am very upset

[MacD]

I had what I thought was an electrical problem with my 2001 R1100R that would be a hassle but not a disaster but boy was I mistaken. (see "strange electrical problem" post)

I had a chafed short where the wires entered the headlight which destroyed all the wiring in the headlight. Well not good but I thought I would follow it back past the chafe till I find good wire and rewire.

Well I followed it back all the way to the fuse box,with melted wires all the way! I've had bikes for 45 years and never have seen a mess like that. What the heck are the fuses for if not to handle a short that sooner or later happens to all bikes?

What I particularly like about BMW's is their attention to engineering details but holy s*** they seemed to have over looked something. Now it looks like I have to replace the entire wiring harness. @*%# @$

OK, enough venting. How long does it take a person with average mechanical skills to replace a wiring harness?

Thanks for listening,

Dennis

[Zot]

Sorry to hear about your situation, unfortunately fuses are only useful when the "short" or "Load" is "downstream of the fuse.

The wire or wires that "feed" the fuse block have no protection.

Good luck with your project.

[chrisstroh]

Seems to me that BMW should have a fuse right at the battery to blow when this happens. I'm convinced the BMW is not a perfect or close to perfect machine-but don't get me started.

[FlyingFinn]

If the R11xxR is anything like R1150RT (and I have good reason to believe it is) there is NO fuse in the headlight circuit at all! So the problem is not that fuse was, in this case, upstream of the short, but there really is no replaceable fuse in the headlight circuit.

 

There is a light relay in fuse-box and that's where the wires go to.

 

I don't understand the design decision to leave out the fuse from that circuit.

 

--

Mikko

[BMT]

Whilst I feel your pain, how is BMW to blame?

 

Sorry to appear unsympathetic, but who installed the headlight modulator? Was the headlight shell really big enough to put those extra pieces in? Certainly the addition of parts and modification to the wiring was not known by the design engineer.

 

Should the addition of the headlight modulator have called for the addition of a fuse? In the headlight circuit, there really isn't much need for a fuse to protect the wiring from overload by the headlight. It's a simple circuit and reasonably predictable in its failure/fault mode (the bulb burns out). The risk of other failure modes was presumably considered to be too low to justify further protection. Not unreasonably, imo.

 

In spite of the retail price, BMW is building a consumer product, not military hardware. It's built down to a price, not up to a specification.

[Boffin]

I don't understand the design decision to leave out the fuse from that circuit.

 

--

Mikko

 

EU vehicle construction legislation does not permit primary lighting circuits to be fused. Not BMW's choice.

 

Andy

[Blue Beemer Dude]

I don't understand the design decision to leave out the fuse from that circuit.

 

--

Mikko

 

EU vehicle construction legislation does not permit primary lighting circuits to be fused. Not BMW's choice.

 

Andy

 

I believe that's a big ditto for USA D.O.T. standards.

 

Additionally, BMW cars have never been known for their electrical component quality. As a matter of fact, many people don't know this, but the mother of Joseph Lucas was German.

 

True fact. You know its true because you read it here on the Internet.

 

Michael

[philbytx]

And his father was Satan....

[bmwmick]

Dennis,

Our local dealer had a similar failure on a customer's bike a few months ago. The actual circuit was the instrument illumination and not the headlamp. The entire wiring harness had to be replaced because of all the burnt wires.

 

Mick

[tomk99r11]

Tracking down the routing may take some time but it should be fairly simple. If you can figure out where the chaffing started you should be able to add some additional protection to prevent recurrence. Good luck. You can probably get a used harness from one of several sources, but you should check on a new one as a used one may be headed the same way yours went.

[MacD]

Crowding was certainly not a factor. The headlight housing is empty except for the headlight wiring and the modulator which is only two inches by three eights inch. I had a headlight modulator in my honda for 15 years and it never blew up. The modulator that was in the R1100 had been in there for three years with no apparent problem.

I found the chafe in the line that most likely caused the meltdown. (see photos at)

http://pg.photos.yahoo.com/ph/dbclark/my_photos

It was located where the headlight wiring bundle entered the headlight housing.

The case where the BMW lost its wiring harness because of a short near the instrument cluster is interesting. Before my bike blew fuses and started to smoke the key stopped working. ie. it would not turn off the engine or the lights.

[FlyingFinn]

EU vehicle construction legislation does not permit primary lighting circuits to be fused. Not BMW's choice.

Andy

 

well, I did not know that. Sounds like a really silly requirement to me.

I can't imagine how that would be good in any situation. Properly sized fuse will only "blow" in case there was a failure somewhere in the system. And having a fuse there would just protect the rest of the system from self-destruction.

 

A better requirement (for cars) I think would be a mandate for independent FUSED circuits for L and R headlight. Then a failure in one system would still leave the other functional.

 

--

Mikko

[RFW]

If the R11xxR is anything like R1150RT (and I have good reason to believe it is) there is NO fuse in the headlight circuit at all! So the problem is not that fuse was, in this case, upstream of the short, but there really is no replaceable fuse in the headlight circuit.

 

There is a light relay in fuse-box and that's where the wires go to.

 

I don't understand the design decision to leave out the fuse from that circuit.

BMW is hardly alone in this. My last bike (an older Honda) had only one fuse in the entire bike, and the headlight was not on it.

 

I strongly suspect there may be some regulations out there that govern this (either DOT, or FAR more likely, TÜV), probably to avoid the possibility of a fuse blowing and lights suddenly going out on a dark road.

 

My 20 year old K100RT also has no fuse in the headlight circuit.

 

In any event, if anyone feels strongly that a battery fuse should be installed, then just do it. It is not rocket science! But be aware that a battery fuse may well be useless in this situation since it has to be sized large enough to handle the entire load on the electrical system, so a short on the headlight wires may not be enough to blow that fuse.

 

Bottom line is that BMW is not a collection of idiots. For at least 20 years, they have had no fuse in series with their headlight. This is no accident! There is a reason for it... either logical that we are unaware of, or far more likely, resulting from regulations.

[FlyingFinn]

Like Boffin said BMW might not be doing this based on their own design decision but are bound by EU regulation.

That being the case, it's not the BMW engineers who are "collection of idiots" but who ever wrote the regulation are.

 

There is no situation when a non-fused headlight circuit is better than fused one. The fuse is there just to limit damage after something else failed.

 

I just happened to have wiring diagrams for 5 vehicles at hand (-02 RT, -00 VFR, -01 KLR, -98 4Runner, -96 Camry) and the RT is the only one with no fuse in the headlight circuit.

 

--

Mikko

[Ken H.]

How long does it take a person with average mechanical skills to replace a wiring harness?

Personal opinion, I don't think I'd go the route of replacing the entire harness. Everything that's on it, from taillight, to ABS to Motronic, to, well you name it, is going to have to be touched.

 

We know the bike still runs right? So little beyond the lighting circuit(s) is likely damaged.

 

Rather, if it was me, I'd tackle it from the approach of tracking down and replacing the damaged wires one by one.

 

The whole thing is a bite, no doubt about it. But with a few hours of tracing & replacing I think the situation is recoverable from.

[ShovelStrokeEd]

I'm with Ken on this one.

 

It is really not all that difficult to make your own harness segment if only the lighting portion is effected. You can take some careful measurements and use nails in a board to secure any small branches you may wish. Then find a place in the original harness where the wires are undamged and secure a multipin connector from Radio Shack (Molex) or better, Amphenol (expensive when you add the tooling but waterproof and better quality). Put the appropriate connectors on the ends of the wires and your done.

 

I just realized what I wrote above and how daunting a task that can be. Sorry. I have had a lot of experience doing panel wiring and harnesses, as has Ken, in fact, I think he does it for a living, and it just seems easy to me. But I have about 2 grand worth of specialized tools for just that work and box after box of connectors and pins, etc. Plus mile upon mile of wires in various colors and gauges.

 

I'll go away now.

[bmweerman]

First...I sympathize with you situation..that's a tough one.

 

BMW does some weird stuff...they build motors that can go 300,000 miles and some of the stuff is so solid and bolted together so well I curse them every time I have to work on it.

 

On the other hand...they really cheap out in some places.

 

For example the little plastic pins that hold the triangular side pieces on the RT....dumb!

 

And my personal favorite...that cheap little plastic piece inside the speedo drive...which my bike keeps eating. Looks solid form the outside, but cheap on the inside. I guess that comes from building them, as someone said, to price not to specs.

 

Things that make you go hmmmmm....

[leikam]

I didn't think that sort of rewiring was very difficult at all.

 

My only question would be just how much wire we're talking about. The wires to the lights themselves are shot, but are the wires bundled with them also toast or just singed? There's a point at which you've lost too much wire to make a repair worthwhile, but two or 6 wires isn't it. In other words, it might be a lot less trouble and expense to repair what's actually burnt.

[MacD]

Hi Guys,

I appreciate all the advice.

The wires that come out of the headlight join with the turn signal, and high, low beam switch wires and they are all welded together. That bundle joins the main bundle and I have not cut into that yet. I have the shop manual and it has great schematics of the wiring with no explanation of what's what. You have to guess by the direction the wires are headed as long as the don't dissappear into a bundle.

Under the gas tank are two connector blocks and the one on the left if you were sitting on the bike has several melted and and fused wires.I have not cut that open to see how far that damage goes.

The ugly news is that I opened the fuse box and saw wire damage below the fuses and relays not much but I haven't dug into all the bundles yet.

I'm researching plan B which is to see if my insurance will cover the damage, minus the deductable of course. There was a fire in the bikes headlight, there are several obvious burn spots. There was a cloud of smoke coming from the fuse box area. Sounds like fire damage to me. I'll know in a few days if they accept the claim. If they don't than I'll go back to plan A and get to re-wiring.

I'm a little concerned that there might be damaged electrical components also ie. motronic, fuel pump, etc.

Thanks,

Dennis

[ednap]

There are often wiring looms for sale on E-Bay and you could also check beemer boneyard.

 

Even if you don't use the entire loom I think it would make patching in the parts you do need to replace a lot easier as it will enable identification.

[tomk99r11]

Not my decision to make but I would opt to replace wiring harnesses rather than pull individual wires. If you have future problems you will better know what wire goes where because at least the wires will have the correct markings. How will you remember what goes where if you just pull wires?.

[ednap]

Here is an example of a wiring harness for sale on E-Bay

 

http://cgi.ebay.com/ebaymotors/BMW-R1150...010228244QQrdZ1

 

Located in Waxhaw, North Carolina, United States