Where to start: non-functioning speedometer 2006 24Ve

[dakota4ce]

I will also add that I checked the power to the triducer and it definitely is receiving 12V across red and ground wires.

I cannot find this gauge online--contact tige direct? There are other Faria Commanders out there, just not this color.

[chpthril]

Does the speed-set work?

IIRC, Faria will fix it for a small fee, if it is the gauge.

[dakota4ce]

I am unsure if SpeedSet works. I had the boat inspected, all of this was noted to work. However, it is turning out to not be true.

[chpthril]

If neither work, its likely a signal issue. if its just the gauge thats inop, its likely the gauge.

[dakota4ce]

Which sucks--third party mechanic inspection. $200 bucks, purported water test, and not noting speedo not working? Give me a break. Oh well, good thing I have a good job I guess.

[dakota4ce]

Any way to test the gauge? Probably not. Maybe pull it and potentially send to Faria....?

[IDBoating]

Sounds like it emits one pulse per rotation (I expected two, but that was just a guess) based on a magnet in the paddlewheel and a Hall effect sensor in the body of the unit. Almost no question the transducer is working properly, which points to something downstream. Next test I'd run is to unplug the cable from the back of the speedo and see if you still see the pulses there. This will check the wiring... you might have lost another splice somewhere and the signal just isn't getting to the gauge.

You're making progress! Run this test and report back!

[dakota4ce]

Sounds like it emits one pulse per rotation (I expected two, but that was just a guess) based on a magnet in the paddlewheel and a Hall effect sensor in the body of the unit. Almost no question the transducer is working properly, which points to something downstream. Next test I'd run is to unplug the cable from the back of the speedo and see if you still see the pulses there. This will check the wiring... you might have lost another splice somewhere and the signal just isn't getting to the gauge.

You're making progress! Run this test and report back!

I will check that. The place where I was gathering evidence of the pulses is only 12" or so from there the green goes into the plug into the back of the speedo, so I was super close already. Still go for it?

[dakota4ce]

I soldered an extension green wire onto the broken off stubby wire emerging from the jacket of wires coming to the instrument panel from the triducer--so I have room to work with. Also solving the differing wire gauge problem with wire crimps that you have expressed disdain for. I checked the "pulses" at this soldered joint with the common on the bare ground wire emerging from the same jacket. All of this behind the dash board.

[IDBoating]

I'd measure it right on the connector that normally plugs into the speedo. Unplug it from the gauge and measure it right on the connector itself. The speedo will only work if it's getting power and signal, so might as well make sure that's happening. If it is, and the gauge still doesn't register, then the only thing left is the gauge itself, yes?

[dakota4ce]

I'd measure it right on the connector that normally plugs into the speedo. Unplug it from the gauge and measure it right on the connector itself. The speedo will only work if it's getting power and signal, so might as well make sure that's happening. If it is, and the gauge still doesn't register, then the only thing left is the gauge itself, yes?

Agreed, yes! I lost my helper to school till 3 or so. No way my wife or 4 year old is gonna pull that off...

[dakota4ce]

I have secured a very high dollar Fluke multimeter from an EE friend of mine--should have a definitive test tonight. IF I can figure out how to operate this Cadillac multimeter!

[IDBoating]

For what you're doing, the el cheapo Harbor Freight is more than sufficient. The next step up would be an oscilloscope, some Fluke meters can act as simple scopes, but you really don't need it. You're already able to see the voltage transitions, now you just need to make sure they're getting to the gauge.

[dakota4ce]

Okay, perhaps what I found earlier was a false outcome. I have the fluke now. It has frequency of DC Volts as a setting. I had it set on the second detent from off and then activated the yellow button for it to read DC Hz.

IMG_4377.jpg

Then I placed the red lead onto the green wire, and placed the black lead onto a known ground from the same bundle of wires. I also quickly tested across the red wire and ground to be sure the unit was getting power, which read 12V (the depth and temp are also working, so it is getting power).

I had my son spin the wheel using an air compressor (very briefly, I know its bad for it)--and the frequency reading never climbed off of zero. I repeated it several times, same result.

Does anyone see anything wrong with this test? It would suggest to me that the triducer paddlewheel assembly is bad. No signal is being sent.


Agree?

[IDBoating]

You have too many variables now. If you had a scope the air compressor test could work, but with this meter I'm not sure what you're reading. "DC" and Hertz are mutually exclusive - DC is steady-state, the opposite of fluctuating or AC. I'm not sure what "DC Hz" is supposed to measure.

When your son was manually turning the paddlewheel, it caused the magnet to move its field toward and away from the Hall effect sensor. That caused the changing voltages that you saw earlier. The changes occurred slowly, so the digital meter on a DC voltage setting could see and display them.

When you spin it with air or water, the changes are so fast that it's an AC signal. The DC setting on a meter may, or may not, display anything depending upon the meter's front end circuitry. Likewise, its AC setting may or may not display anything depending upon the frequency and its front end circuitry. This is why a scope is so powerful, it displays EXACTLY what is happening regardless of DC, AC, offset, spectral content, etc.

Go back to the test you know yields results: Slow manual rotation while watching with the simple meter set to DC volts. Repeat the previous experiment and confirm identical results. THEN, move to the gauge connector and confirm you have signal there while the paddlewheel is rotated at the same speed as before.

When testing things, change only a single parameter at a time. Otherwise you don't know what you are testing.