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  1. #1

    Default How can I test VSS ?

    My Baker DD6 comes with a OEM Vehicle Speed Sensor. I'm direct wired to a Autometer speedo/tach unit, but am not receiving any pulse when calibrating. Is there a test I can perform to verify if the VSS is working. I pulled and cleaned the unit, so thats not an issue. Everything, RPM, indicator lights are all OK. Thanks.

  2. #2
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    First verify your wiring.

    Assuming you have a three wire sensor the connections should be:

    Red 12V Ign
    Blk GND
    Green SPD terminal on gauge.

    Make sure you are connected to the SPD terminal and not the VSS terminal on the Autometer gauge.

    There is a terminal labeled VSS - it is an output and goes to the TSM on a factory set-up. It is the signal the module uses to self cancel the turn signals.

  3. #3

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    Thanks. Wouldn't happen to know any particulars on which sensor Baker uses? Linda says it's stock Harley, but the Autometer tech sheet states either a 5v or 12v sensor may be used. I had the bike wiring roughed in, and a shop finished it up. Didn't get to participate due to the social distance deal, so I'm familiarizing myself now. I don't see the unit fused as recommended with a 1 amp... good idea to cut one in?

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    I run the large autometer speedo/tach combo with an aftermarket sensor. Most stock VSS are three wire 12v sensors but it's hard to say without looking. it is a little challenging to test the sensor output without a good multimeter or scope - but with a good multimeter or scope it is not too difficult. The sensors are typically very rugged and go many many miles without failure.

    It's hard to advise without knowing your level of skill with electrical stuff and wiring, and basic testing.

    Still feel your best shot is to first verify the wiring is correct - then suspect a bad sensor.

    As I understand your post - this has never worked as opposed to was working then failed?

    ...

  5. #5

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    My testing skills are limited... Initially all was good, a couple months back the voltage regulator went south and overcharged the battery, fried a Badlands module, and the Autometer unit. I checked continuity and resistance on the wiring, replaced affected parts. Everything is jake except I'm receiving no pulse. I need to drain and pull the tanks to get at the wiring properly. I'll try to muddle through any testing procedure you think applicable, I have a decent multi-meter. I need to get educated on automotive electrics.. period. Are there any online courses that you'd recommend ? Thanks again for taking the time

  6. #6
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    Good Info -

    Since everything was OK before the voltage regulator went bad it's a pretty good bet that all is wired correctly.

    The sensor / speedo needs a couple of things to function correctly.

    You need to verify that you have 12V at the red wire to the sensor with the ign on. You need to look at this as close to the sensor as possible. You can use a small needle to pierce the insulation close to where the wire enters the sensor then measure voltage from there to ground.

    You need to verify continuity of the black wire to ground - should read almost zero ohms. Use a needle to connect to that wire as well.

    Finally you need continuity from the green wire on the sensor to the SPD terminal on the AutoMeter gauge. Use the needle for this test as well. Should read close to zero ohms.

    Use liquid electrical tape or nail polish to seal the needle holes in the wires - you don't want water in there to cause corrosion.

    If these three items are good you either have a bad sensor or a bad speedo. Best bet is the sensor, could have been taken out along with the gauge when the regulator failed.

    You can attempt to look at the sensor output pulse but this is iffy depending on your meter. Some have a frequency counter function that will read the pulse signal, others will read it on the ac volts scale but it sometimes is hard to determine if you are seeing a good or bad output. A graphing meter or an oscilloscope will tell you for sure but most folks don't have one of those in the garage.

    Sensor voltage, ground, and continuity to the gauge checks will narrow it to the sensor or the gauge. Shouldn't have to pull the tanks to do this.

    This all assumes a factory 3 wire 12v sensor. If you find a different set-up come on back and describe what you find - better yet a photo or two would be great..

    Good luck with it.

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