1992 K75S ABS light constantly on

[98lee]

The battery is new and checks out as having a very good charge

Checks out how? 10.4 volts is NOT even 10% charged.

I'm still having trouble locating where a black wire with a round terminal coming from the right side of the instrument cluster is supposed to be attached. There is already a black wire with a round terminal attached to the throttle assembly which I assume carries the ground

Could it be the other end of the wire going to the throttle assembly?

A picture would be helpful.

[broadstone]

Lee, I rechecked the brand new battery and charging strength and found the static battery voltage to be at 12.3V and 13.8V at the battery with the engine at fast idle. One thing I forgot to emphasize in previous posts is that the headlight, parking light, speedometer, tachometer, gear indicator and high beam indicators all work.

* I mis-stated the voltage; I should have said 12.4 not 10.4

*the counter gear to ABS sensor distances are within specs

* Front turn indicator bulbs are good and there is no voltage going to these sockets

* All harness connections to the front end appear to be plugged in

* Flasher relay and harness seem to be OK because rear turn signals flash but flash fairly rapidly.

* As far as the horn goes, I've had horn problems with 2 other BMW's, both of which were related to bad grounds. I'll get to that later.

Lee, this bike has so many issues that it almost appears to have been sabotaged but the more effort I put into it the more my feeling of ownership grows. My new seat arrives today and I have all but abandoned any thought of parting with this resurrected machine. Now, if I could only find some pearl white touch up paint. Thanks once again. Jim

[98lee]

Check for voltage at the front turn signal harness to main harness connector (in the headlight area). If none, it's either a cut in the main harness to the flasher or a bad flasher (flasher relay has separate output connectors for front and rear).

Take a jumper to the horn with 12v to test the horn.

Don't give up, you're getting close.

Is the seat you ordered a factory low seat?

[broadstone]

I thought I should update my last post. On the issue of the non-working front directional signals, I found that there were bad ground connections at both light terminals. They now work. Also, all the instrument lights are working including those associated with light testing and ABS function. The only indicator questionable at this point is the low fuel light which stays on, but I only have about 1/3 or less fuel in the tank so that may not really be a problem. I'm close so as soon as I lubricate the driveshaft splines I'll feel safe riding it but I'll contnue trying to solve the ABS problem. It runs and rides great now with only a hint of valve noise. Thanks again. I'll stay with it to the end.

[Zagando]

Jim; The low fuel light coming on with a 1/3 tankful is normal. I ride around on reserve for days, go to a gas station (Chevron has Techron which is good for all Ks) and it'll take maybe only 3.5 gallons or so to fill her up.

I understand that if this early warning bothers you there is a way the long float arm that is part of the fuel sending unit inside the tank can be bent (downwards, IIRC) so that it will come on later. Then it'll better reflect a reserve amount.

Glad to hear that you're getting close and try to post some pix when you can. That pearlescent white is a nice color, isn't it?

[broadstone]

I've taken my/our quest a bit further trying to diagnose my ABS problems. A summary of this process is:

1. Initially, when the ignition was turned on, ABS light came on and stayed on.

2. I reset the ABS using the wire to the center terminal of the diagnostic plug method.

3. Reset worked to the extent that now, when I turn on the ignition, the ABS light flashes and activating the brakes turns off the bulb monitoring light. But, in riding the bike, the ABS light continues to flash.

4. I tried determining where the problem is counting the diagnostic code blips using a digital voltmeter. In doing this test multiple times I didn't get completely consistent counts but mostly code #6 indicating a defective relay or low battery, if my count is accurate.

5. I checked the battery again and found the voltage to be 12.8V.

6. The tank is not off but, when I turn the ignition on I do hear a click indicating that at least some relay is activating.

7. I found a great write up by Milky Way Technology Japan which described the diagnosis further; their article said that when the ignition is turned on, within 5 seconds there will be a sound "like a mosquito" from the rear brake modulator. I hear no sound of any kind.

I am not sure that my diagnostic code blip count is accurate not being sure where the first blip starts because it looks to me like the first one is immediate. If I wait for the first voltage drop after the first voltage reading is displayed, then the count would be 5 instead of 6 indicating low voltage which I know is not the case.

One of my concerns regarding this procedure is, what would be an indicator of no measurable faults. Would the count continue to 9 blips? Also, although no code indicates a gap problem between the sensor and the counter ring, and i really don't know how the sensor reads the speed, mine are rusty and I'm wondering whether this could affect the diagnosis.

I could just turn off the ABS and I will, I suppose, if the fix looks like it will get very expensive but I've had 3 other BMW's with ABS and one with iABS. Because I live in south Florida where rain is common, and because I'm not a fair weather rider, I really want the ABS working. Any suggestions will be appreciated. Jim

[Zagando]

Sounds to me like Fault Code 6 which is the main ABS relay (simple fix, install new relay in the box under the tank).

Fault Code 5 is the low-battery condition and with a resting voltage of 12.8 it should not be that at all---unless you didn't successfully reset the ABS. Sometimes it takes me a few tries to get it right with the wire and holding the switch, etc.

Do you not live near a Radio Shack? I first used my digital voltmeter to diagnose faults and while it works, you have to get the hang of counting the voltage drops before you can be sure.

A 276-011 from Radio Shack is so much easier to use! Best $3 you'll ever spend on your bike. You'll know almost instantly once you hook it up and watch the little blinks---no second-guessing at all.

Btw, I am checking out my old ABS relay to see if I can get it working again---if I do I'll PM you in case you're interested (they're on the expensive side when new so if I can fix it I'll put it up for grabs in the Flea Market soon).

Good luck sorting this last annoying bug out, Jim. This same scenario happened to me only a month or so ago---but I'm kind of glad it did---it led to a whole bunch of other things that I had neglected or overlooked and now my bike is better than it ever has been.

Now if winter would turn around and head back North or wherever it came from I could go on a long ride!

[broadstone]

Well, thanks to much help from BMWMOA I am now riding my high mileage K75S and am loving it. Having 168,000 miles clocked, aging, and having suffered much neglect and abuse, it runs as well as the other 2 low mileage 75's that I owned years ago. After nearly a month of diagnosing many electrical problems, repairing a leaking tank, replacing a wiring harness and injectors, seat, etc., I feel a sort of closeness toward it that I never really had with my previous 9 BMW's. However, there are a couple of remaining issues that I need to address somehow. I turned 70 this past June and, because of the several issues that attend getting older I need a lower seat to feel safe and comfortable, especially at low speeds (the newer stock seat that I bought through eBay didn't help) and coming to a stop.

Also, it appears that I need an ABS computer and the tires are somewhat dried out. To correct these issues along with the low seat conversion, the expense will be significant so I have a decision to make. I'm trying to decide if I should cut my losses, sell this bike at a loss and buy another lower mileage K75, or stay with this one, spend more money and still end up with an unmarketable motorcycle because of the high mileage.

I know this is a personal issue, not a technical one and I will ultimately have to figure it out on my own but advice from you guys is always welcome. Anybody have a K75 for sale, preferably with a low seat?

[dbrick]

There's much to be said for a bike you know, as you've worked on and repaired it.

I wouldn't let the tires scare you off. Yes they should be replaced, I think if they're more than four years old (some folks won't ride on tires even if they're three), but there's no guarantee that any new-to-you K75 won't also need tires. Tires are a periodic expense, and they'll come up sooner or later anyway on any bike.

[deilenberger]

I know this is a personal issue, not a technical one and I will ultimately have to figure it out on my own but advice from you guys is always welcome. Anybody have a K75 for sale, preferably with a low seat?

I know this will be looked on as heresy, but I'd suggest buying a bike you're more comfortable on. I did and never regretted it. Lots of more mature riders find the R1200R (light weight, easy to get lower) appealing, for the same reasons you have - maneuvering at low speeds and pushing bikes around parking lots and such. I know of one used - reasonably low miles - '07 nicely farkled for $7500 (a steaming deal IMHO..) And it has working ABS that is far superior to the first generation on the Klassic-K. It's on another forum. PM me and I'll send along the link.

If that isn't an option - I have a few suggestions:

o - skip the low seat. It's not that much lower and it is much less comfortable. The problem with the Klassic-K seat isn't just height, it's width due to the frame rails the seat must fit over. The low seat is no narrower, so your legs are splayed out as badly as on the standard seat, the actual loss of height isn't what you would expect.

o - consider lower suspension. Works Performance makes some reasonably priced lower shocks and springs. Besides freshening up what would be a very tired suspension (if still original) - these items have reasonable resale value when you do decide to sell the bike.

o - consider longer legs. Sounds silly, but there are boots available that can add about 3/4" to your inseam. I believe it's Dayton who makes them (but could be mistaken on that), and it is not obvious that there are lifts in the boots when you see them. Adding a taller sole to your existing boots may also be an option for a lesser cost solution.

o - use a lower profile tire. I ran my K100RT on 80 series tires instead of the stock 90 series. This gains you about 3/8" (and if you're short of inseam, every bit helps) with no decrease in ride quality. Bridgestone used to make ones that were the same width-diameter, lower profile.. they were a big help in reaching the ground.

HTH,

[broadstone]

Thanks and your right, Dellenberger; bringing up the R1200S on this brick site could be seen as heretical. Although I consider the 3 cylinder to be the best of the K bikes and generally prefer the K over the R bikes, I also really like the classical feel and appearance of the R. I've never ridden the R1200S but my last R bike was the R1150 which is also a little tall but a wonderful ride.

I thought about the suspension modification and lower profile tires but that also gets a little pricey for a bike with the history of mine. I already pay attention to my footwear and found that an old pair of riding boots of mine work pretty well but I wear shorts a lot and they look pretty goofy when I do. Vibram souls are out because I found that when needing to find or get off the pedals quickly, they can hang up.

Anyway, I didn't know anything about the R1200S but, even though I'm pretty stuck on the K75S so I'm willing to check out that option. You said you know of a good deal?

[deilenberger]

Anyway, I didn't know anything about the R1200S but, even though I'm pretty stuck on the K75S so I'm willing to check out that option. You said you know of a good deal?

Not the "S" - the R1200R, and I'll PM you with a link to the one for sale..

Ah - too late. The owner came to his senses and decided to keep the Roadster..
http://www.r1150r.org/board/viewtopic.php?f=5&t=25669

You might want to watch that forum - the R1200R's appear with some regularity there. And go visit your friendly local dealer and see if he has one for a test ride. Take your check book..