Full Version: Speedo quit on me!
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I thought I seen somewhere on this site about how to test the speedo but I just can't seem to find it.
It started reading erratically and now I got a big "O". this is the digital dash. Last year it did the same so I took the front wheel off and checked the gears in the front hub and everything was in good shape. I greased everything and put it back together. A couple days later it started working again.

Now I got nothing, the mechanical mile counter is not turning, the digital one isn't working and of course the turn signal canselor isn't working ether.

So, what is the best way to test this and find out whats going on?
Speed Sensor lnspection

Disconnect the speed sensor from the speedometer gearbox at the front wheel.
Connect a voltmeter across the Black/Brown and Black/Yellow terminals of the sensor white 3-P coupler.
Turn the ignition switch to ON.
The sensor is normal if the voltmeter needle swings from 0 to about 5 slowly eight times when the sensor drive shaft is turned slowly one full turn.

[Image: speedsensor.jpg]


Thanks Tricky. I'll check it out after work tomorrow unless it gets too cold. Thanks again.

Now do I get to it by why of the headlight or do I need to pull the dash?
You should be able to find it by removing the head light,

On Interstate and Aspencade, rotate the rear view mirrors on their mounts about 90degrees
Remove the mounting bolts.
Actually you only need to remove the top bolt and loosen the lower one
Protect the headlight with a shop towel to prevent damage to the headlight lens.
Remove the windshield trim by lifting it with a screwdriver.
Remove the headlight garnish.
Remove the headlight mounting bracket, and garnish bracket. bolts. trim holder.


Thanks Tricky. Now my problem is I've been working till its dark, its too cold to be just standing outside and I don't have a garage. Can you fix that for me too. :lol:

I did ride the wing to work today and the two previous days. At least I got to do that. Now there talking about 7-8 days of snow :cry:

Oh well, I'll get to it some time soon. The one thing about it is I really don't need a speedo but its a nice Luxury. 8)
I could fix that, I have a heated two car or rather one motorcycle/snowblower/one car garage, but it would be a little tough to get here at this time of the year. Smile

That speed sensor sure helps with the auto volume control though


I've never had that auto volume control working. I don't use or have headsets. Isn't that the only time it works? I'm just guessing. Let me know if I'm wrong. Maybe I need to fix it too.
The auto volume works with the radio through the speakers. you can adjust the amount of auto volume by using the knob next to the tone controller. But if your speedo was working and isnt now it could be the speed sensor. That is where the auto volume gets its signal via the radio.

You need the speed sensor to tell the speedo what speed your doing and also it tells the radio when you go slower to lower the volume.


Thanks for letting me know. My radio hadn't worked for years but this winter I sent it into sierra to have it fixed. I got it back and a week later it messed up again so I just sent it back today.

I'm guessing that sense the radio never did work right to begin with I just forgot about the auto volume. When I get the speedo working again and get the radio back again, I'll give the auto volume a try.

Thanks for enlightening me on all of this.

I might be looking for a speed sensor soon. Anyone got an extra?


Little question, is the auto volume part of the GL's radio or amplifier? I.E. if you replace the radio dose the auto volume still work?
It's hard to say by looking at the schematics.

[Image: basicradio.jpg]

but I would guess its the power amp, which is unusual because in most home equipment the power amp supplies a constant power and its the pre-amp source which is controlled, at least thats the way I have read it.

When you say replace the radio, do you mean replacing by one of the same ie: Type III Panasonic or an after market radio.


I'm thinking aftermarket. Just something I'm wondering about right now. Radio's are pretty low on the priority list right now.
If installing an aftermarket radio in place of the Type III I am not certain whether the after market radio could be wired in to take advantage of the options available to the original, such as the auto volume and intercom whjich are part of the system.

Possibly if purchasing a unit capable of tapping the pre-amplified circuit, they are available in some top end units, you might be able to feed the Type III power amp with the L+R feeds but using the up & down channel selector switch and the muting switch might pose a somewhat more difficult situation.

If your tempting to fit an after market unit replacing a broken type III, personally I would spend the money on having the original unit repaired by Sierra, it might be cheaper and a lot less of a headache.

If you putting a radio into an Interstate just stick the radio in and do without all the added features of the Aspencade.


Hey Tricky,
I tested my speed sensor and it checked out good. Who knows, when I ride it next time it might be working just fine. Is there something else I should test?
Is the tach working?

L.C.D. Meters
NOTE: For access to the couplers behind the meter, remove the mirrors, windshield trim and trim holder bracket.

Input Voltage lnspection

If the meter does not work, measure voltage between the red terminal of the white 4-P coupler and body ground.
Battery voltage should be indicated with the ignition switch on.
If there is no voltage, check the 7.5A sub fuse inside the fairing.

It sounds like there is voltage to the meter if it reading "0" though.
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