K75S electric issue

[ortme]

I rode my 1987 K75S for about 100 miles yesterday.I had just installed new heated grips and wanted a test ride. She ran well then, but now does not shut down. Had to pull the + battery to shut down . Now without key in and engine cut -off -switch in either the off or on postion, it lights up all electrics like an amusement ride. Fuel pump whirrls, All turn lights flash together, high beam on etc. as I connect the battery terminals.
Could this be a bad started relay ?
Glen

[deilenberger]

I rode my 1987 K75S for about 100 miles yesterday.I had just installed new heated grips and wanted a test ride. She ran well then, but now does not shut down. Had to pull the + battery to shut down . Now without key in and engine cut -off -switch in either the off or on postion, it lights up all electrics like an amusement ride. Fuel pump whirrls, All turn lights flash together, high beam on etc. as I connect the battery terminals.
Could this be a bad started relay ?
GlenQuestion: Were these the factory heated grips? Installed at the takeoff point in the wiring harness (left side of the frame under the tank?)

Usually - when I hear of something like this happening when someone is doing electronics - it means something isn't installed correctly - not that a component such as the start relay failed.

IF the starter relay has failed - the starter will start spinning as soon as the battery is connected - and I don't see you reporting that. I do see you reporting multiple powered on components - that don't necessarily have any common electrical point. That sort of worries me - it's usually a sign that something very bad has happened inside the wiring harness.

[blake]

sounds like in the process of hooking up your grips you bypassed the ignition switch.
go back where you just were and check your wiring.

tell (or show) us where you made your connections.

[ortme]

Thanks for the reply
My heated grips are the cheaper wrap type. Not the standard BMW or Hot Hands etc.
It also does engage the started motor with the key off and the engine cut off on or off, as I hook up the battery only.

I wire my electrical hand heat as follows :

Negative battery to 12v 30A automotive relay pin 86 (ground)
postive battery with in-line fuse to relay pin 87
tapped into tail light bulb wire to relay pin 85 (it hot with the key on)
Relay pin 30 to toggle switch for grips
Glen

[ortme]

I discovered that a host of wires were melted that lead out of the control box to a connector for the left hand switch assembly:doh
Cause and effect / how I wire my heated grips ?
Looks like I need a complete wiring harness to deal with possible other melts.
electrically challenged
Glen

[deilenberger]

I discovered that a host of wires were melted that lead out of the control box to a connector for the left hand switch assembly:doh
Cause and effect / how I wire my heated grips ?
Looks like I need a complete wiring harness to deal with possible other melts.
electrically challenged
GlenI'd suggest exactly that. A new harness is silly expensive, but used ones can be found. Most of the K75 bikes used a pretty much standard harness - the only differences are usually in the area where the fairing might be. Since you have an S - the one off an RT should also work, and perhaps the one off a C..

One consideration is if you have ABS or not (which you don't unless it was added on your '87) - you want a non-ABS harness.

Replacing it requires disassembly of a LOT of the bike (BTDT) - tank off, rear trim around the seat off, front fairing completely off. I'd suggest finding some numbered tags - and as you disconnect something on the bike - number both ends of the connection with the same number - and then look on the replacement harness and number the connector there with the same number. This makes reconnecting things MUCH easier.

I'd also suggest documenting where the harness runs and is tied to the frame using a digital camera. Take extensive photos - you'll be referring to them.

Figure on it being an 8 hour job.. BTDT on my '87 S..

[98lee]

I'm going to go out on a limb here, and guess you didn't tell us the whole story.
Like the part where you replaced that pesky fuse #2 (7.5 amp) that kept blowing with a higher amperage one.

The reason fuses are sized the way they are is to protect the WIRES. If you put a larger fuse in a circuit and then add a higher load (Heated grips ??amps) the fuse may not blow but the wires that were sized for a maximum of 10amps may now be seeing what ever the new fuse is. This could cause the wire to overheat and meltdown.

Like I said , just a guess. If it is the case though, let us know how many amps the grips are rated to draw and what size fuse you put in fuse #2. We can probably figure out a better way to wire these. (once you've replaced /repaired the harness.):thumb


:dance :dance :dance )

[deilenberger]

Lee,

I agree - we do seem to be missing part of the story here.. but one consideration.. there are a number of unfused circuits on the K bikes - including the lighting circuits.

BMW seemed to feel it was better for things to melt down then for the lights to suddenly go down. Unfortunately - a number of people have had spontaneous meltdowns caused simply by internal shorts in the harness. I've dissected K bike harnesses - and there are spots where the bundles of wiring are really tightly packed. Mate that with a too-tight tie-wrap holding it to the frame and you have a scenerio for a wiring harness meltdown.

One friend lost his K11 to a bike fire - started from the wiring harness.. and he hadn't put any overside fuses in.

[ortme]

Lee
Thanks for any ideas.
No, I didn't change any of the fuses so maybe Don Deilenberger's idea of tapping into a light circuit that isn't fused could have set forth my melting.
I did find locally a wire harness from a 1992 K75S for $50.00.
It is an ABS harness and my old 1987 K75s wasn't ABS
I label all parts and matched most connectors.
The control box is very different.
Glen

[deilenberger]

Lee
Thanks for any ideas.
No, I didn't change any of the fuses so maybe Don Deilenberger's idea of tapping into a light circuit that isn't fused could have set forth my melting.
I did find locally a wire harness from a 1992 K75S for $50.00.
It is an ABS harness and my old 1987 K75s wasn't ABS
I label all parts and matched most connectors.
The control box is very different.
GlenYes it is - there are half-size relays in the control box instead of full size (they needed the room). You can ignore anything with a blue connector. Blue is for the ABS system - including at least one (mebbe two - it's been a while) relays in the E-box.

You probably can make it work - but if it was me - I'd look for the right harness.

[BuddingGeezer]

Give Phillip Engel at Enguland European Motorworks. I have bought several used K bike parts from him. He has an Ebay store but is soon advertising in BMW ON. Can probably save you a bundle if he has it. I just dealt direct with him this week. Straight up guy. I think he is even a member of this organization.
1-866-675-1453.
Tell him Ralph in Arkansas said to call.

[deilenberger]

You might also consider BeemerBoneYard..

http://www.beemerboneyard.com/61111459253.html

http://www.beemerboneyard.com/61112305516.html

[98lee]

Don,

I don't know what I am missing.

The scematic for an '87 shows the taillight getting it's power from the bulb monitoring controlbox, which is fused by Fuse #2.

When you pull Fuse #2 the taillight goes out.

Unless there is multiple power sources to the controlbox (which I haven't yet checked for) and it acts like a relay, I would think the taillight IS fused.

I'll double check tomorrow.


:dance :dance :dance

[98lee]

Ortme,

How many Amps (or Watts) are those grips rated at?


:dance :dance :dance

[deilenberger]

Don,

I don't know what I am missing.

The scematic for an '87 shows the taillight getting it's power from the bulb monitoring controlbox, which is fused by Fuse #2.

When you pull Fuse #2 the taillight goes out.

Unless there is multiple power sources to the controlbox (which I haven't yet checked for) and it acts like a relay, I would think the taillight IS fused.

I'll double check tomorrow.


:dance :dance :danceLee,

The taillight circuit may be fused (have to look at a diagram - I don't have a K bike anymore) - but the headlight circuits are NOT. More than one person had the harness melt down due to this.

[ortme]

Hello Helpers
I decided to not try installing the ABS harness from the 1992 ABS K75S. I have instead purchased a 1987 K75S harness from Beermerboneyard as Don advised.

The wiring diagram shows fuse #2 going to a bulb monitoring unit to which the tail light is wired.

However,I was also running Hella lights off of the Headlight wiring. I had tapped the yellow wire there and this yellow wire ran to a box diagram label horn switch ,Dimmer switch ,left turn signal switch. Then this yellow wire goes to a box labeled "connection for special equipment." This last "box" did have a connection to fuse #5 but by another wire out from it to this fuse.
While I had this lighting set up for 3 years prior to my latest hand grip wiring, my low bean had fail on my last ride and the wires at the headlight were part of the melt down.

So it goes
Glen