Sudden Bright Generator Light R90/6

[asulliva]

Red generator light came on steady, bright red without any warning. My accessory voltmeter went to zero volts. Headlight and instrument lighting works normally. The engine shut down normally with the key. Upon turning the key back on, the red generator light is off (not normal) and there is no response to the starter button. Voltmeter still reads zero.

Bike has had no previous electrical issues. It also has a Hannigan fairing, which means a major task to check fuses in the headlight shell. I'd rather eliminate other likely causes before tearing the fairing off the bike.

I've seen lots of discussion of dim red generator lights, but no fault isolation procedures for sudden and complete charging (my guess) failures.

Thanks,

Alan Sullivan
1974 R90/6

[asulliva]

An additional detail on my problem: NONE of the warning lights illuminate when the ignition is turned on (Neutral; Oil; Gen). As before, headlight/instrument background lighting still work. Thanks,
Alan Sullivan

[Motor31]

Have you put a meter on the battery and checked the voltage? Sounds like a short in part of the wiring harness.

[Boxerkuh]

Need more info... are the turn signals working? What about horn button and brake lights? It may be the switches on the handlebar... did this happen all of a sudden? Does the bike start and run or is this totally disabling the bike?

[asulliva]

Excellent questions; let me go home and check out the functionality of all of the electrical features. What I know right now is: that the gen light came on suddenly and solidly while engine was running; none of the warning lights work once I turned off the motor (and turned key back to "on"); the headlight and instrument illumination lights work, pushing the starter button has no effect; the voltmeter reads zero (will check battery, but it's obviously got some voltage in order to illuminate the headlight). More as I get it.

Thanks,

Alan Sullivan

[Polarbear]

Bright red light can mean the voltage is too high from alternator,"perhaps"? It is supposed to regulate the voltage to a max of around 14 volts coming to the battery from alternator. I've heard the regulator can fail and up to 18 volts can pass, which is too hot for the system, any system. You can make a very simple test by passing the regulator with a jump wire in the three prong plug to the regulator. I'm not an electrical mechanic, but would definately go here to look see. Good luck, Randy13233

[asulliva]

Fellow Airheads,

I've rechecked the bike and found the following: battery voltage from positive to negative terminal is 12.4 volts (pretty impressive given the futzing around I've done since the red gen light came on bright and steady); headlight hi and lo beams and instruments lights work; turn signal and brake lights (front and rear brakes), horn and starter are ALL inoperative. No warning lights. Voltmeter reads zero with the key ON. Bike is immobilized due to this electrical issue.

Can anyone suggest a logical diagnostic chain for these symptoms (e.g., Step 1, Step 2, etc.)?

Thanks,

Alan Sullivan

[donbmw]

Have you checked the fuses.

Don

[asulliva]

The bike has a Hannigan fairing, which means a major task to check fuses in the headlight shell. I'd rather eliminate other likely causes before tearing the fairing off the bike.

Having said that, I agree that fuses are a very likely suspect. Any others of equal or greater liklihood?


Thanks,

Alan S.

[Bobmws]

The bike has a Hannigan fairing, which means a major task to check fuses in the headlight shell. I'd rather eliminate other likely causes before tearing the fairing off the bike.

Having said that, I agree that fuses are a very likely suspect. Any others of equal or greater liklihood?


Thanks,

Alan S.

Before you remount the fairing, you are going to remove it, get some remote fuse holders.

[donbmw]

A little time to check fuses could be cheaper than anything else.

Don

[nhlkats]

headlight hi and lo beams and instruments lights work; turn signal and brake lights (front and rear brakes), horn and starter are ALL inoperative.
Yes, too coincidental that *that* whole set of things went out at once.
This similar situation happened to me once at a restaurant parking lot.
Came back out to the bike and boom, wouldnt start, half of the electricals worked, the other half didnt.
Turned out to be some wire underneath the tank going into some relay (it was dark).

I guess my best advice is, if you haven't taken the fairing off yet, is to take the tank off and look carefully for any obvious disconnected wires and such. Have the key to on with the one of the turn signals on, and just kind of go over the frame of the bike, touching random wires and packs of wires, making sure that it doesnt all of a sudden just cut back in to operation if you touch a wire. That was how I found the problem, in the dark, in that parking lot. Long shot, but hey...
Otherwise, check fuses next. After that, rip open the headlight bucket, start checking for shorted wires, corroded connections, disconnected wires, etc.
Hope that helps.