Topic: Struggling with oil pressure and neutral lights

[ralt12]

This is my last resort, really. The instrument I have from Cognito is the GPS Large tach/small speedo single instrument (https://cognitomoto.com/collections/gauges/products/cognito-moto-gps-speedo-and-small-tach?variant=1332926657), and while it's really a nice unit, it doesn't have a neutral light or an oil pressure warning light. So I sourced a couple of LED's and made up a bracket. They are the type where there is a positive and a negative, and have to be hooked up correctly to work. i have the M-unit pretty much licked, I think, but I still can't get the two LED's to light when ignition is on. They're powered on the positive side from one of the AUX outputs, and the negative goes to the oil pressure switch and the neutral switch. Does anyone have an idea regarding how I'm fouling this up ? The large instrument works as intended, lights work, turn signals work, high beam (and it's indicator ) work, etc. Waiting for the tank, etc . to get back from the painter to see if I can actually start it.

[newday777]

Test out your wiring with an incandescent bulb instead of the LED. I've read that LED bulbs won't work on oil pressure circuit.

[calj737]

LED bulbs will work for the OIL and NEU indicators, so that is not your issue.

Using two simple wires, run one to battery + and the other to battery -. Test the bulb directly to the battery. Does it work? If not, reverse the wires. Does it work?

If it worked in either of those circumstances, then it is time to use a meter on the wires to the bulb to confirm voltage there. Let us know how you fare.

[ralt12]

Bulbs work fine when grounded (that is, in their bracket and powered by one of the AUX outputs on the M-unit blue, but then the wires that go to the oil pressure warning light and the neutral light get grounded). I have continuity from the case to the body of the oil pressure sending unit, but nothing where the wire screws to the unit. I'm assuming that the switch is a normally on switch (when the engine is off), so that when pressure is present, the circuit is cut and the light goes out. So I'm also assuming that the switch has failed. The neutral switch is in that mode (failed) as well. Both worked fine before the work commenced, but I guess these things happen.

[calj737]

So if you use a meter, on the wire at the switch itself, key ON, are you saying neither OIL or NEU have continuity to NEG?

[ralt12]

Grounded my oil warning light at the switch (unscrewing the lead and grounding to the case). Light comes on. I guess I have a bad sender. Adding pressure pneumatically on the bench doesn't do anything. No continuity from the body of the switch to the sender at rest. Same with the neutral indictor, though I may want to run the bike a bit before declaring another death, maybe it's just in a deep sleep having not been run for quite a while.

[ralt12]

So if you use a meter, on the wire at the switch itself, key ON, are you saying neither OIL or NEU have continuity to NEG?

Yes. Seems unusual that both would take a dump at the same time.

[calj737]

Did you paint the engine cases, or powder coat them? Is something preventing the switches from contacting the case, and then making its way to battery NEG?

It is very unusual that both switches would be die simultaneously. It is more likely something something in common with the assembly phase. 

[ralt12]

Did you paint the engine cases, or powder coat them? Is something preventing the switches from contacting the case, and then making its way to battery NEG?

It is very unusual that both switches would be die simultaneously. It is more likely something something in common with the assembly phase. 

I did the top end only; it was a low mileage example and was nicely tight, seemed pretty happy, so I left the bottom end alone. So no engine case repaint, just the head, cylinder block, and cam cover. The body of the switch had continuity to the engine ground and NEG. I've ordered up a replacement switch, and if it doesn't work then I'm really ready to tear my hair out. Only thing I can think of is it sat for a really long time, and like a lot of older equipment, is a lot happier when it gets exercise, and unhappy when it doesn't . We'll see if the new switch helps.

[ralt12]

As it turned out, the oil pressure switch had failed, which was a little surprising given that it worked not that long ago and sat in dry heated storage. I’m going to let the neutral light sit for the moment, and see if when we get the bodywork back from the painter and the front brake lines addressed if it will loosen up by use. Always have the option to go back in to rebuild it.