Back again 1500SE Electrics

The grounds. I'm guessing your lights work when in neutral? Probably the gang connector on the left side of the frame about even with the front of the fuel tank. It's orange, taped into the harness.

Johnno SA said:

Please who can tell me what is the connection between Gear selection and rear light function.

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DaveO430 said:

The grounds. I'm guessing your lights work when in neutral? Probably the gang connector on the left side of the frame about even with the front of the fuel tank. It's orange, taped into the harness.

Click to expand...

DaveO430 said:

The grounds. I'm guessing your lights work when in neutral? Probably the gang connector on the left side of the frame about even with the front of the fuel tank. It's orange, taped into the harness.

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I have traced all ground lines from back to front, all relays work, no fault in multi ground connector.
Reverse diode and park diode are all good. all gear connections at engine control unit to ground are good.
I just cannot fathom what is wrong or links gears to back lights.

Why don't you start with describing the problem?

As far as i know there is nothing connecting the rear lights and gear change!

DaveO430 said:

Why don't you start with describing the problem?

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After carrying out oil change etc. I discovered that the rear lights and flashers malfunctioned when any gear was selected. Everything worked perfectly in neutral. Select any gear 1st to OD and select left or right flasher apply brakes front or rear flasher stops and all back lights flash. hazards don't work either! Re select neutral and all systems work as they should.
Hence my frustration...

If you have already checked the connector I mentioned before I have no idea. Your particular problem is common and has always been in that connector.

Sounds like a classic ground fault. Shouldn't be that tough to trace with a multimeter. Do you have the wiring diagram?
Are there any aftermarket lights?

RambozoClown said:

Sounds like a classic ground fault. Shouldn't be that tough to trace with a multimeter. Do you have the wiring diagram?
Are there any aftermarket lights?

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I have been tracing all ground wiring shown on wiring diagrams in my shop manual, using multi meter. At this time only the front fairing is on the frame.

Johnno SA said:

Please who can tell me what is the connection between Gear selection and rear light function.
1990 1500SE

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It’s called VOLTAGE FEEDBACK. This occurs when a circuit is not properly grounded or has a failed connection.
Clean all grounds and all connections!
Pay close attention to the connections on top of both fan housings.

Johnno SA said:

Please who can tell me what is the connection between Gear selection and rear light function.
1990 1500SE

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Maybe try removing one light bulb at a time to see if you can isolate the problem area. Reinstall the same bulb if i doesn’t change things until you find the issue. Just a suggestion, another way to troubleshoot. Good luck and happy new year.
ride smart. Bob

You say you did an oil change and etcetera. Another approach, I suppose would be to go back through everything that you did to the bike between the last time it worked correctly (assuming it worked correctly when you did the oil change and etc.) and now. Maybe you'll discover that you damaged some wiring or pulled something loose.