Oil Light Stays On--Think it's an electrical issue

On my '82 M2, I recently swapped the speedometer. Afterwards, the oil light stays on with the engine running. Because of the work I did on the speedo (including connecting/disconnecting wires in the headlight bucket), I'm thinking that most likely the issue is electrical, and not an actual problem with my oil pressure.

Checked my oil level--it's fine.

I checked all the wire connections in the bucket and at the oil switch, and everything looks like it is connected right. I have full continuity on the wire from the sensor to the connector in the headlight bucket.

When I start the engine, I can see the oil light dim as I rev, but it never goes out.

I checked my FSM to see if there was a prescribed method for testing the switch sensor, but there was no information at all, other than the wiring diagram.

Does anyone know how I can test to make sure the sensor is working properly? Any other tests I can run to confirm if the problem is electrical?

If it is a mechanical problem with the oil system, what are the most likely culprits? Blocked pump screen?

I probably should also mention that my bike has an oil cooler (from a KZ1100, if I remember right).

Update:

After posting, I remembered that I had an extra oil pressure sensor (from when I swapped out the connector to add the oil cooler). So I swapped the sensors, but there was no change. So it is unlikely that the sensor is the problem.

I'm open to suggestions on where to start looking to figure out where the problem is.

Thanks.

Is the oil filter clean and fresh and otherwise in good condition?

If doubtful about filter, could remove it and test run engine momentarily without a filter to see whether that makes any difference.

Good Luck!

As you most likely already know, this is a pressure transducer...

Transducer Definition: Converts one form of energy into another, in this case, pressure to an electrical signal.

In the KZ motor, under low pressure conditions, the switch contact is closed thus passing engine case ground (battery ground) up to the instrumentation lamp thus illuminating it. Once the engine case is pressurized the switch opens (no ground being passed) & the lamp goes out under normal operations.

Ok, down & dirty, unplug the sensor electrical connection for testing and start the engine.

Does the lamp still come on?
If so, you have a short to ground somewhere in your harness that is passing (ground) to the oil lamp bulb.

Unfortunately I don't have an electrical schematic for your model or I could get you down closer to the actual conductor to look for.

"I recently swapped the speedometer."
I'd take the instrument panel apart and have a closer look internally... Chances are the oil indicator bulb is receiving a bad connection/partial ground. With the ignition switch on, +12Vdc is passed to the bulb and just sits there waiting for the provided ground through the pressure switch...

Hope this helps, let us know how it works out...

OMR

Thanks guys.

Patton, the oil filter "should" be okay. I change it fairly regularly--though it has been a few months. I don't put a lot of miles on this bike, however.

OMR, thanks for the info. I'll try your suggestions and see what I find. If that doesn't reveal any answers, I'll start looking at the filter, and for other mechanical problems.

I'd remove the sprocket cover and check the wiring that runs inside it. On the larger 4's the alternator,side stand switch,neutral switch,and oil pressure switch all bundle together and sit in a channel at the back above the engine sprocket. Possibly a loose/dirty connection is causing the light to partially come on.