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Discussion Starter · #1 ·
I cannot get the oil pressure light to operate as designed.

I have replaced the sensor with a new one, problem remains.

The sensor has just one wire (blue/red). Is that wire supposed to be energized when the ignition key is in the ON position?

Thank you.
 

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1983 Honda vt750 Shadow
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The light gets power to the bulb with the key on, and then through the bulb filament, down to the switch, where it is grounded to light up the bulb.
Get a piece of wire and connect it to the battery negative post and with the key on touch it to the end of the oil pressure switch It should light every time you ground it - unless the bulb is bad.
If that works fine the pressure switch is bad.
 

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Discussion Starter · #3 ·
((The light gets power to the bulb with the key on, and then through the bulb filament, down to the switch...))

The wire connecting to the sensor will be energized when the ignition key is in the ON position?
In other words, I can remove the wire from the switch, put my test light on it, turn the key to ON and my test light will come on, right?

Thanks for your help again Swifty.
 

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Yes the test light will provide a ground for the dash bulb,it may light only dim, but should at least light.
 

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Discussion Starter · #5 ·
When I disconnect the wire from the oil sensor, then connect my voltmeter to the wire, then turn the ignition to ON, how many volts should the voltmeter display?
 

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Maybe up to battery voltage except the bulb filament may draw it down a little.
 

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Discussion Starter · #7 ·
When I check the voltage on the wire like I described, my voltmeter reads 0.00 volts.

According to the wiring diagram in the Clymer book, that wire (L/R for blue/black) is a home run to the oil pressure light, so why would it have any voltage?

The only other wire connecting to the oil pressure light is a B/BR (for Black/Brown) wire that is a ground (I think). Wire B/BR ends up at the fuse panel...all fuses are intact and OK.

As part of my troubleshooting, I applied battery voltage to the L/R wire (by way of my PowerProbe tool) and the oil light did succeed in illuminating.

That test ought to prove that the ground to the light is good, right? (It would not illuminate without a ground).

I ordered another pressure sensor.

I followed the L/R wire up the harness and pulled apart the first connector. That connect has 3 wires:

1. The L/R wire from the oil sensor
2. A G/O wire from the "change switch" (neutral/overdrive), that connects to the overdrive indicator light
3. A G/R wire from the "change switch" (neutral/overdrive), that connects to the neutral indicator switch (and, indirectly, to the diode)

When I turn the ignition key to ON and measure the voltage, I get the following:

1. The L/R wire - 0.00 v
2. The G/O wire - BLANK - literally no characters displayed
3. The G/R wire - 4.3 v

I don't understand where the oil light is supposed to get power from.

By the way, my neutral position sensor does function properly.
 

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The black/brown should get power with the key on from a fuse and it goes to the bulb.
The other side of the bulb, blue/red, goes to the oil pressure switch to be grounded and light the bulb.
The bulb doesn't light when you ground the blue/red wire?And the bulb is good?
Maybe a high resistance connection at any of the connection points.
 

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