Dim taillight Q?

[Don R]

I've been ignoring the dim lights, haven't noticed anything getting worse. I tested that new old stock switch with no voltage improvement. I did clean a few connections and add a pair of ground wires, one to the taillight area and one to the frame near the engine ground. I still have the Polaris rec/regulator in place under the seat and my plan is to remove the old R/R and put a Bosch relay there to feed the switched fuses directly from a blade fuse holder.
I helped a friend with wiring on a 52 chevy street rod truck who had a poorly wired fan relay tonight. That got me thinking about it again.

 

[grcamna2]

Don,what's the output of your bike's voltage when you touch a voltmeter to the + & - of the battery terminals while it's running at different rpms ?

 

[Don R]

I've lived with the GS1100 for a while now and gotten the new carbs and jetting process underway. I got a new old stock ignition switch from Japan and see no difference in voltages at the fuse panel or improvement in the brightness of the lights. The charging system is working properly, battery tested, and load tested and replaced. I checked the rotor spinning on the crankshaft, polished, lapped it and re-tightened it.
The path from the main fuse/red wire to the switch and back through the orange to the other three fuses still loses a volt even though I cleaned the contacts and tried the new switch.
I've followed the wiring diagram in the Haynes manual and see how the light switch gets power from the red/white, white/green and the orange. Green/white was fed from the alternator and white/red was fed from the V/reg.
The Polaris regulator is wired directly to the battery. I may swap to a blade type fuse holder and try to power these two wires through a fifth fuse. The new Rec/Reg is under the seat where the air cleaner box would be and the old style one is still in place, when it is removed it will leave a nice place for a relay if needed.

 

[Don R]

I was studying the wiring diagram in the Haynes manual, I looked at the red/white and white/green that go to the headlight switch, they formerly connected the V/Reg and the Alt. through the headlight switch. While checking with the engine on and lights on high, blinking etc. I felt hot wires in the bundle near the battery.
It was the red feed from the main fuse towards the ign. switch. While following the hot red wire into the harness I discovered another unconnected red male end. So, I made a jumper, male to double female bullet connectors and plugged both reds into the main fused feed. Now, no wires are getting hot, the voltage at all fuses is higher and I'm assuming volts and both ends of the bike are higher also. It's daytime but the lights seem brighter. With a full tank the gas gauge now goes all the way to 3/4. That's also an improvement.
I don't understand it and also am willing to accept the idea that I don't need to.

The charging volts at the battery are within spec, engine on and off, another load tested new battery, the alternator wires all have been tested multiple times, AC volts are good, nothing to ground, flywheel not spinning on the shaft, the charging system is working fine. New polaris/indian style regulator. ground wires added. Issues were in the harness. Hopefully cured.
WooHoo!

 

[grcamna2]

I was studying the wiring diagram in the Haynes manual, I looked at the red/white and white/green that go to the headlight switch, they formerly connected the V/Reg and the Alt. through the headlight switch. While checking with the engine on and lights on high, blinking etc. I felt hot wires in the bundle near the battery.
It was the red feed from the main fuse towards the ign. switch. While following the hot red wire into the harness I discovered another unconnected red male end. So, I made a jumper, male to double female bullet connectors and plugged both reds into the main fused feed. Now, no wires are getting hot, the voltage at all fuses is higher and I'm assuming volts and both ends of the bike are higher also. It's daytime but the lights seem brighter. With a full tank the gas gauge now goes all the way to 3/4. That's also an improvement.
I don't understand it and also am willing to accept the idea that I don't need to.

The charging volts at the battery are within spec, engine on and off, another load tested new battery, the alternator wires all have been tested multiple times, AC volts are good, nothing to ground, flywheel not spinning on the shaft, the charging system is working fine. New polaris/indian style regulator. ground wires added. Issues were in the harness. Hopefully cured.
WooHoo!

Yeah !!
I'm glad to hear you have your electrical system sorted Don;happy Labor Day weekend.

 

[Rob S.]

Happy for you. I think we all deserve a bigger pic than your avatar of the bike that beat the GPz 1100 in the quarter mile in 1981! :welcoming:

 

[Don R]

Thanks, I've yet to master the art of shrinking a pic that will copy on this site. I've tried the bike of the month submission multiple times.

 

[Datsa Noydb]

Nice to see that you (might) have your problem solved, but for anyone else using this for a reference, do a quick voltage check as part of your troubleshooting process. No not the usual type, one that isolates parts of the system.

I don't know the details on the wiring layout on your 1100E, but most GSes have the same basic layout. Under the tank, you will find the connector that goes to the ignition switch. There are usually four wires in it: Red, Orange, Gray and Brown. With the bike running, put your voltmeter probes in the red and orange parts of the connector. You SHOULD see a number very close tom if not actually, ZERO. The larger the number, the more voltage you are dropping in the switch contacts themselves. If the red/orange drop is not bad, check the red/brown contacts. The brown wire has its own contact in the ignition switch and goes straight to the tail light, so it could be bad (giving you low voltage output) even though the rest of the bike is good.

 

[Don R]

Thank you for that info. I'll have the tank off soon to re-jet the carbs so that will be a good time to check it.

 

[Don R]

I got in an after dark ride tonight, the lights are significantly brighter than they were before connecting the hidden wire. I was behind my wife in her car and she noticed the difference. I may still do something in the way of an LED taillight.
My GL1000 has a pair of additional Drag Specialties lights in the back, they are running and brake lights, next to the license plate. I like the added light but the style is wrong for a GS1100e.