So, I finally got a chance to work on the brick again after getting a set of nice looking used instruments. The entire panel functions except,
The odo/trip meter,lighting for the cluster at night,
and both fuel low indicators don't work.

To all knowing K wizards, what do you think is wrong with the lighting and odo trip meters? I am pretty sure the low fuel lights are burned out but who knows?

If its on the K....

The odometer issue may be electrical as in absence of signal

Check the rear wheel sensor is actually working...check the plug connector into the loom, inside the right hand battery cover.......remove the sensor from the final drive and clean it......you can also test it.

The fuel lights if both not working they get signal coming from the plug at the front left of the gas tank.....[early tanks having 7/4l warning have the connector front left]. So check for blown bulbs as well as signal.

Make sure all the pins on the cluster are clean and with good connections.

I am inclined to figure its connections along the way. Have you neutral light, gear indicator etc all good?

After that its a case of gong inside it and others will advise you on that.

Heres a list of everything that DOES work Speedo, needle reads right, Nuetral light, warning light, choke light, high beam light, both turn indicator lights all work. Tacho works. Turn indicator reset works, everything BUT the following works perfectly, so does the gear indicator!

No odo or trip meter, and button to reset the trip meter is missing but I have mine off the old cluster, but it wontr reset the trip meter. no instrument lights in that the cluster is not lit at all at night (except the lights mentioned)
and no low fuel indicator lights. 

Now, those lights WERE working on my old cluster before I pulled it off sooo. ?

What wire on the cluster provides power for the instrument lights?

The tripmeter knob is not engaged correctly with the reset bar. Pull it out gently towards you and rotate/release a little at a time. At some point it will engage and settle in closer to the side of the panel. If the whole assembly is loose then you're missing the spring on the inside.

Lights: pins 13, 18 and 24. 24 is the power feed (+12v). Pins 13 and 18 are both earth; pin 13 does the two top corners and pin 18 the two bottom corners plus the bulb under the clock. If none of the five bulbs are working then pin 24 is your suspect.

Dai wrote:The tripmeter knob is not engaged correctly with the reset bar. Pull it out gently towards you and rotate/release a little at a time. At some point it will engage and settle in closer to the side of the panel. If the whole assembly is loose then you're missing the spring on the inside.

Lights: pins 13, 18 and 24. 24 is the power feed (+12v). Pins 13 and 18 are both earth; pin 13 does the two top corners and pin 18 the two bottom corners plus the bulb under the clock. If none of the five bulbs are working then pin 24 is your suspect.

Thanks! I'll give them a test this evening. Thanks again!

Is there a pin out diagram to show me which pins are which?

Pull the two plugs out of the instrument panel. The pins have embossed numbers in the plug recess.

Ok, weird, pin 8 (I think) is MISSING on the NEW cluster, and the old one has 23 pins with one missing which looks it came that way. The new cluster has 22 pins, two rows of 11, whilst the old one has 23 pins two rows of 12 with one missing in one row. I just decided to take the logical route, and take the components out of the new cluster I needed to work in my old cluster and now I have a completely working (for the most part) cluster! Now the only issue I have is I forgot to swap the gear indicator from new to old and two cluster lamps dont work. Now the two lamps that dont work must be the flex cables connections because I tested ALL LAMPS and replaced all those that tested bad or looked dim. All the lamps I installed are known working lamps. I do remember now the same two lamps that now still don't illuminate never did on my bike. Sooo, I'm well chuffed at the result because I now know how fast I'm going, how far, and if I need to make a stop for petrol!

Dai wrote:Pull the two plugs out of the instrument panel. The pins have embossed numbers in the plug recess.

Many thanks I see that and used it for testing and repair....thanks again!

Old cluster = 7L and 3L fuel warning lights
New cluster = 4L fuel warning light only.

The new cluster won't display fuel level as it relies on a variable resistance at the rear of the fuel tank, whereas your original one worked from a pair of thermistors through the four-pin connector on the left-forward side of the fuel tank. So, yes, swapping boards has saved you a lot of grief. I believe that 1985 was the changeover year, so asking for a 1985 instrument cluster is a bit of a lottery.

Don't assume that the lamps are not at fault because you tested them. Pull the bulbholders and with a small screwdriver, force the internal contacts closer together. I've had a few bulbholders where the bulb was okay but the holder wasn't gripping it tightly enough.

Dai wrote:Old cluster = 7L and 3L fuel warning lights
New cluster = 4L fuel warning light only.

The new cluster won't display fuel level as it relies on a variable resistance at the rear of the fuel tank, whereas your original one worked from a pair of thermistors through the four-pin connector on the left-forward side of the fuel tank. So, yes, swapping boards has saved you a lot of grief. I believe that 1985 was the changeover year, so asking for a 1985 instrument cluster is a bit of a lottery.

Don't assume that the lamps are not at fault because you tested them. Pull the bulbholders and with a small screwdriver, force the internal contacts closer together. I've had a few bulbholders where the bulb was okay but the holder wasn't gripping it tightly enough.

Now see, that's the other odd thing. I am starting to think there are an early and late 1985 or a cross over model because the new cluster has both the 7l and 4l low lamps, and looks EXACTLY like mine except for the number of pins. And the new one (which only has 32K original miles on it) is in excellent shape. The new one is not only missing two pins, it doesn't holes for either of the missing pine in the lower cover. So, it obviously never was intended to have more than 22 pins where mine has 23....as said, pin 8 is the one missing. What would that pin be for? And why would it be missing on the newer cluster? The only things not working on the new one were the odo trip meter and lights for the cluster....I have the old one all working by swaping in the new components so its not an issue but I'd love to know.

Installed old/new cluster. I have this remove and replace thing down...can have instruments off, apart, and back together in fifteen mins now! 

Pin 7 and pin 8 are the fuel level senders. Someone smarter than me can tell you which one is which (7L / 4L), although I suspect that pin 8 is the 7L light. If you're that good at taking the cluster apart , check that pin 8 hasn't just broken off the flexiPCB. I have seen pins come off.

As for holes/not holes, I know of at least three different rear covers for the instrument cluster and there may be more. Could be that you've got a mix'n'match that isn't the one you need.

Could be as I know nothing on the history of the cluster I got as a replacement for mine. Now I can say the new one has a back panel pass thru for the pins that has no hole for the two missing pins....

I'll also say that before I starred looking for a replacement cluster I asked here and everyone said that out there are two types, one that has both the 7l and 4l lights, and the that has only the one light. The first having square pins, the other round. So I was told if the new cluster had both lamps and square pins it would work.....just my luck I probably got a bluster that. Had been built for a one year early or late bike and not specifically for my 1985 k100rt. A stocker on back written in handwriting said 1985 k100/ k75 so I'm not sure what it really came off of. I was told by the seller it came off of a crashed 1985 k100rt.....

No such thing as a 1985 K75 (first year was 86 and only had the single low fuel lamp) so since yours has both the 4L and 7L lamps then it came off of an 85 K100.

I think it's correct that Pin 7 is the 4L light.

I'm pretty sure both of those got a ground signal from the sender so you could test those by putting 12V to Pin 6 (switched power from a green/black wire) and grounding Pin 7, Pin 8 or both to see if they illuminate.

Anyone know what lights the gear indicator lcd? Mine works but is only visible in some conditions, and when I say one works, the lcd shows the number correct but looms like an lcd that the back or side light has gone out on.

Interestingly I needed a new cluster for the 84 K100RT as it stopped displaying speed and no odo and it wasn't the rear when sensor. I eventually picked one up locally, off an 84 K100RS. When I went to fit the 'new' one the back plates were different, despite having the same part no embossed on them. However it all worked.....except the clock which Dai organised a fix for.

The 7/4l cluster goes with the bolted down gas tank that changed here during 1985.....

I am back at the clusters now because my new K100RS cluster works fine, has neutral but does not display the gears.....

SniperX wrote:Anyone know what lights the gear indicator lcd? Mine works but is only visible in some conditions, and when I say one works, the lcd shows the number correct but looms like an lcd that the back or side light has gone out on.

You've possibly got one that's dying. I'm assuming that 'visible in some conditions' means looking at the LCD directly over the top and that any movement away from that 90-degree angle causes it to fade?

You could try to use an eraser to clean up the contact pads on both the PCB and the back of the LCD unit. It often helps.