Warning lights

[GreMonte]

So my bikes new trick is to turn on the oil and side stand warning lights while I'm riding. They also go out and back on seemingly at random. Of course I looked down to see the side stand was up and I also stopped and checked the oil which was on the full mark ( I had also just done an oil change as well)

So do I have a short? Or does the bike light off every warning light when it senses an oil problem?

The bike is an 83 GS750T

[tom203]

Did this just happen after oil change?Probably not, so I'd disconnect kickstand switch and see what happens.

[81gs1100]

I think the ground of the warning light is shared with the ground of the side stand switch with a diode keeping the connection from going backwards to the light. There should be a little blade like fuse with the markings of a diode on it? I would need the wiring diagram to know for sure.

[GreMonte]

Thanks for the quick reply. In fact it did do it after the oil change but it was the de-winter oil change. I'll try unplugging the side stand for a simple test too. I will let you know what I find out.

[spyug]

Have a look at this : http://www.thegsresources.com/_forum...d.php?t=191994

In addition, have a look at my recent posts in in the engine section concerning oil pressure and oil pumps. Do not ignore what you are seeing, it might be low oil pressure such as what I am experiencing at this time.

If you read through the posts you will see that low oil pressure is signalled by both the side stand and oil pressure lights staying on. The lights are ganged together and you will find if you disconnect the oil pressure sender wire, your OP light will go out and the side stand light will then function normally. This could indicate a faulty OP sender if you are lucky or if unlucky it may be signalling a low oil pressure scenario.

You can check the function of the sender by removing it from the engine and blowing some compressed air into the hole. It should be connected to the wire, grounded to the engine and the key should be on. If a shot of air causes the light to go out, the sender is good.

As its an intermittent issue I'd say its probably failing and you will likely need to change it. If you do change it and the issues persist then you have other problems. Hopefully you don't.

Good luck and let us know what you find.

Spyug

[GreMonte]

Thanks Spyug, Now I have focus and things to test. I love my bike and as much as I want to swap a 1100 in I don't want to do it because I have to. When all the lights came on it only took me a half block to stop and check out what I could.

[Redman]

So my bikes new trick is to turn on the oil and side stand warning lights while I'm riding. They also go out and back on seemingly at random. Of course I looked down to see the side stand was up and I also stopped and checked the oil which was on the full mark ( I had also just done an oil change as well)

So do I have a short? Or does the bike light off every warning light when it senses an oil problem?

The bike is an 83 GS750T

Short answer: Yes, the oil pressure switch is suppose to operate more than just the "oil" light.


Some things to understand (some previous postings not entirely correct)
- Oil Pressure Switch (OPS) does make the oil light AND the sidestand light come on. The OPS works by connecting its wire to ground when oil pressure is low.
- The Side Stand Switch (SSS) should make only the side stand light come on. The SSS works by connecting its wire to ground when side stand is not all the way up.
- If this sounds like it is not possible, well, it is the diode being there that makes this possible.

- if you pull wire off the OPS and want to test things: having the wire off simulates good oil pressure. Shorting the wire to ground simulates low oil pressure (both lights on).

- if you pull wire off the SSS and want to test things: having the wire off simulates the sidestand being all the way up (light off), shorting the wire to ground simulates the sidestand not being up (light on).

If only the sidestand light come on when sidestand not up and engine running... and if both lights on when engine off and side stand is up........then you know that it is the OPS circuit that is turning on both lights.

Run engine till oil light goes out, then operate the side stand. With oil pressure okay, the side stand should operate onlyh the side stand light.

A problem with the diode would not make both lights come on when neither should be on.

But a certain problem with the diode could make both lights operate by the SSS.

If you remove the diode then the OPS will operate only the oil light.

Study this till you understand it. Then operated it and see what you observe.
Seems to me that the OPS is what is flashing your warning lights. Now, why is the OPS signalling low oil pressure, that is another question, more of an engine question, less of an electrical question.

.

[GreMonte]

Spent some time with the bike here's what I found. Side stand light would not work with side stand down. Easy fix, the double nut was loose and the switch was not in its home and the hook thingy was unhooked. That's all fine now. With the sprocket cover off I found something that might be the oil sender, is that where it is on an 83 750T? Anyway oil lights still come on but I have a new question about how the oil is checked. Is it like a Chevy tranny and you check it with the bike running? On the center stand and off the bike reads on the full mark but not when its running. If checked when running that means the bike hold about five quarts of oil? If I have been checking the oil wrong then I owe my bike big time.

[Redman]

Not familar with 750s, but on 850G and 1100G it is on top of trnasmission, right behind cyclinders. (not under any cover, under cover is the gear posiotion sender)

So you got the sidestand switch working.
You did not say if you were all set with the oil light and the sidestand light, and now understand how it is suppose to work?

About checking oil:
- engine off for a while
- bike on center stand
- look in sight glass, should be between L and H.
- if not on center stand, hold bike upright, and level will show higher than when it is on sidestand.


.

[GreMonte]

Found the problem. The wire going to the pressure sender it totally disintegrated. The lug came off in my hand and took a couple strands of the conductor with it. The insulation is garbage. I will replace the entire wire and that should fix it. I know I have oil pressure because my valve cover gasket is leaking lol. Already replacing that.

[surviverguy]

Good news. Glad you found the problem. A new wire and you'll be good to go!

[Redman]

Found the problem. The wire going to the pressure sender it totally disintegrated. .....

And .... ?

And ... the bare conductor was then grounding out to the engine or frame..?

That wire connected to ground (usally by the oil pressure switch detecting low oil pressure) is what would make the oil pressure light and the sidestand light come on.

.

[GreMonte]

Still looking for a place to hook my new oil pressure gauge too. I wish it was as easy as the other engines with the big bolt right by the oil filler cap. I don't really want to run a T fitting off the current pressure sender...any ideas?

[surviverguy]

If you remove the oil pressure sending unit, then you wouldn't need a "T" to connect the gauge. Is this a mechanical or electrical type gauge? A mechanical gauge would require a hole in the cover for the oil line to pass through. An electrical type gauge would be easier as the wires could come out with the ignitor signal wires.

[GreMonte]

If you remove the oil pressure sending unit, then you wouldn't need a "T" to connect the gauge. Is this a mechanical or electrical type gauge? A mechanical gauge would require a hole in the cover for the oil line to pass through. An electrical type gauge would be easier as the wires could come out with the ignitor signal wires.

Yeah its a mechanical gauge. If I leave the electrical wire to the sender unplugged with the light stay out? Will my side stand light still work right?
So guys here kind of made me feel like removing the sender for a gauge was a bad thing to do. I dunno I always liked gauges better than lights.

So if this is my preferred oil pressure port than I'm on my way to installing my new gauge, Thanks for the reply.

One more thing

Don't you just love it when the problem jumps out and screams ME ME ME ME!!!!