Mystery Switch?

[Farmrjohn]

I have just acquired a '94 K75 and it has a switch that I can't find in the Rider's Manual or by searching online.  Also, just to confirm, the heated grip switch is a three way, with the center position "off", the top position "high" and the lower position "low", correct?

Here's a pic. of the mystery switch, the one on the right.

[Scott_]

Are you sure it's just not a blank filler?
See if you can see/feel around the backside for any wires in that specific spot.

[Martin]

+1 Scott it does not look as if it has been used, different patina to the others.
Regards Martin.

[The Mighty Gryphon]

Does the switch rocker move?  If not, it is a filler.  If it does, it could possibly be that a previous owner installed it to manually turn on the radiator cooling fan.  These bikes are infamous for getting very hot because the fan does not automatically come on at a reasonable temperature so many owners install manual switches.

It is also possible that it was used for running lights.

[TimTyler]

That's the Weed Butter switch.

[Laitch]

That's the Weed Butter switch.

Also makes Weed Cheese if run longer.

[WayneDW]

I have one like that which turns on/off the running lights.  But you probably would have noticed that... 

[Farmrjohn]

Are you sure it's just not a blank filler?
See if you can see/feel around the backside for any wires in that specific spot.

There are wires going to it, and it does feel like a switch, with an click "on" position if pushed at the bottom by the little arrow icons.  There are no running lights installed, but I don't know the full history of the bike.

[Laitch]

There are wires going to it, and it does feel like a switch, with an click "on" position if pushed at the bottom by the little arrow icons.

Time to trace the wires, john, removing the tank if necessary. It'll be fun and instructive. You do have a workshop manual, right? Have you had the bike running and rocked the switch yet. It could be wired to start the cooling fan—a useful modification.

[Elipten]

Or the elevation plug.  I have that on my bike.

[Laitch]

Or the elevation plug.  I have that on my bike.

That's nifty, I guess, for alpine dwellers' roundtrips to the flatlands for groceries.

Then again, it could be just unconnected bare wires—a testament to some rider's unfulfilled dream. :falldown:

[Laitch]

Also, just to confirm, the heated grip switch is a three way, with the center position "off", the top position "high" and the lower position "low", correct?

It shouldn't take you too long to determine that yourself with a running bike, one bare hand on a grip and the other working the switch in between providing sips of a comforting beverage.

[motodude]

Yup. I got one of those too. I used a flasher switch, rubbed the bottom of the delta off and now it is a, "mountain"!

Tom

Or the elevation plug.  I have that on my bike.

[Farmrjohn]

OK, I've traced the wires from the switch into the wiring loom, but where they go from there is still a mystery.  I'm hesitant to operate a switch not knowing what it does.  The two wires from the switch are connected with bullet connectors into a portion of the loom (second photo) that joins some other sleeved wire and goes into what I think is the fuel injection control unit (at screwdriver tip, 1st photo).

[Martin]

What colour are the wires it would be useful in determining where the go. Do you have a wiring diagram.
Regards Martin.

[TimTyler]

Do you have a high altitude plug outlet?

If you don't I bet that's what the switch is wired to.

[Laitch]

Do you have a high altitude plug outlet?
If you don't I bet that's what the switch is wired to.

The switch is wired to a plug that isn't there? Now that's just plain spooky, Tim.

[TimTyler]

All right. To be clear... The switch might be wired to the leads that once connected to the high altitude plug.

Fucker.   :deal:

[Laitch]

 :hehehe

[Farmrjohn]

Between the time I posted the photos, going down to look again, and the above responses, that's the conclusion I came to as well.  I didn't see a high altitude plug outlet as depicted in yellow and don't see a plug attached to the frame.  The wiring loom/harness that continues to the fuel injector control has a portion of it that does look like the outlet.  Now, how can I determine what switch position closes the circuit, providing the "high altitude" signal?  I'm hesitant to pull apart the bullet connectors to check with a multimeter, but suppose that's the best way. 

[TimTyler]

If the switch is ON then you're compensating for high altitude. The middle position on the switch will be OFF.

Remove the switch from the dash using your fingers or remove the dash from the forks with a hex wrench.

[Martin]

According to the Minister for Finance & Recreation the wire colours are green with red tracer & white with red tracer. I had her verify as I'm red green colour blind. :hehehe Oz is too flat to require an altitude plug but we could do with an attitude plug.
Regards Martin. 

[rbm]

I'm relaying how the Jetronic reacts to the TPS.  According to the Bosch Jetronic Technical Manual, when WOT is detected, the ECU attempts to enrichen the air-fuel mixture, targeting lambda=0.85-0.90.

With this mod, at partial open throttle and if the switch is thrown, the ECU will open the injectors for a longer period of time, allowing more fuel to enter the combustion chamber, lowering the AFR.  If the PO was attempting to emulate the high-altitude plug in an attempt to get the bike to work better at high altitudes, (s)he ended up going in the wrong direction.

[Laitch]

That makes sense to me, Tim. What I'm not understanding is how the connection made by the switch would differ from the connection made by adding the loop in the plug. I would have thought that adding the loop triggered increased air flow at altitude. What is the indication that this switch doesn't emulate it? I can't tell by the halftones how it's wired.

[TimTyler]

...how the connection made by the switch would differ from the connection made by adding the loop in the plug.

It doesn't. It's just easier to flip a switch.