Going crazy! Need speedo help!

[91hawk]

I'm trying to fix an erratic speedo on my 2003 XB9s. Everything works. The needles sweep when key is turned on, odo, trip odo, clock, lighting. . . all is well. But the speedo needle won't go over like 20 mph on the street and maybe 50 on the freeway. I also have an XB12s with a normally-functioning speedo so I swapped the speed sensor (cleaning it first), since that's a common problem. Same thing. So, leaving that sensor on, I swapped the entire instrument module over! Same darn thing! Everything worked except speedo wouldn't crest 20 mph!

Next, I tore in to the wiring. I tore the whole under-flyscreen area out and now have great access to the wiring loom. As far as I can tell there are no broken or chaffed wires. I tested continuity between the blk/wht (ground) wire that plugs into the speed sensor and the headlight module plug-in. It's fine. Next I tried the white wire. Same thing: Continuity.

Then things got confusing! The wiring diagram (which I can hardly read in the shop manual it's so blurry) shows that the 3rd wire coming from the speed sensor is green/yellow. Mine is RED? And it matches a red wire on the other side of the connector going up to the headlight module plug-in? I tested continuity between both of what I ASSUME to be that wire. Nada. No continuity.

Now I'm kind of stalled out!

Any help GREATLY appreciated as I sit in pile of removed parts, multimeters and jumper wires!

 

[Cooter]

Here's my guess, and it's a total guess…

Was you old speedo sensor really gummed up?
The speedo sensor reads off a reluctor wheel in the final drive of the trans. Pull the sensor back out and see if you can see in there (sometimes taking a close-up pic with your phone helps, but you'll need light).

I'm guessing the reluctor wheel is gummed up with metal shavings? (clean with air pressure), or out of line/worn down/bent? (all bad things).

Look at the schematic. Does the speedo sensor wire go through the ECM? Test for continuity between the sensor/ECM input, and also between speedo/ECM output. I doubt you'd get continuity through the ECM (input and output).

 

[91hawk]

Thanks! I'm on it!

 

[91hawk]

I took the sensor back off and checked inside the hole with a small mirror and bright flashlite! All look shiny in there but I've got the bike up on a stand and I'll pull spark plugs tomorrow and turn engine over w/rear wheel to make sure the sender-trigger thingie looks good 360 degrees around.
I have continuity on white wire from speed sensor plug back to ECM and from ECM to instrument module plug.

I have continuity on ground from sensor plug back to ECM but NOTHING from there?

 

[91hawk]

Put bike on stand today and bumped engine with rear wheel through 360 degrees and reluctor wheel looks shiny and clean all the way around. No crud at all.

Went back and checked continuity:

A is speed sensor female end
B is ECM plug-in
C is instrument module plug-in

B/W grd) from A to B. . . YES
Wht (sensor) from A to B...YES
Red (5V power) from A to B. . . YES
So from sensor to ETM it's all good!

B/W (grd) from B to C. . . YES
Wht (sensor) from B to C. . . YES
Red (power) from B to C. . . NO

However I figure that being a power wire, it might come from somewhere else? The problem I'm having now is that I CAN'T READ my shop manual wiring diagrams. They are blurry! I can find sections of the wiring diagram on google images that are readable but the complete diagrams are too small. . .

Anyone READABLE wiring diagram??? That would be awesome!\

Thanks!!!

Rick

 

[thrstrmech]

which part of the diagram, pg #? if you're still having issues, download the manual from buellmods.com. the service manual and parts catalog for the '03 is there.

 

[91hawk]

Thanks sooo much. I can read them! Back to work!

 

[joebuell06]

My buddy has a very similar issue on his 05 XB9Sx. We have traced the wires in the head unit and checked the speedo, also, but haven't found any irregularities. Please let us know what the problem is as soon as you can or have corrected it.