2002 FLHTC. I haven't ridden in three weeks and went on vacation for a week. Decided to hook up the battery tender before I left. Came home, disconnected the battery tender (light was green) and I tried to start the bike this morning. It acted like it wanted to just for a moment and died. The left side relay under the seat is BUZZING! I have minimal power (dash lights, some indicators). All connections are tight and clean, battery tests to 12.86 volts. HELP! Thanks! Don Liller

 

Replace the relay. It sounds to be stuck partically closed. The buzzing is the arc it's striking inside. Enough resistance across the gap to drop the voltage so the starter doesn't run, but still enough current to drop your voltage.

 

Sooo...I replaced the relay this morning. Still buzzing when I turn on the ignition switch. BUT, I now hear an intermittent clicking inside the fairing! Now what? Don

 

Sorry, I jumped to a conclusion I shouldn't have. I assumed it was the start relay when you hit the start switch. It still seems likely it's the start relay. I'm not sure of differances from year to year, but on mine the start relay has a metalic casing and is on the left. The system relay is black and on the right. Both next to the fuses.

The system relay controls the injectors and ignition coil so shouldn't draw much power with the bike not running. It should be closed all the time so it opening and closing shouldn't be a problem. If it won't close you just crank and don't start since you get no fuel, with EFI, and no spark. The start relay controls the starter solenoid. The starter can draw quite a bit of power without having enough power to actually turn the engine over. So if that circuit is on when it shouldn't be your lights are likely going to go dim. If it got enough power to actually crank then the problem would be obvious, i.e. turn on the ignition and the start runs. If didn't have enough power to actually crank though it might go unnoticed. I would expect it to hum though. Like a big industrial exhaust fan humming as it powers up until it starts getting up to speed.

The relay itself humming should be the controlling power for the relay. Particularly now you know the relay is good. Sorry about that, I should have said test it. It could be it's not getting enough power to actually activate so it's humming as it as the moving parts vibrate rather than actually moving. The lights dimming and all would take quite a draw off a full charged battery to do. Nothing normally does that so it would have to be a short.

So one thing would be pull fuses to find what circuit. You aren't drawing enough to blow fuses, but 15A is a pretty strong draw. If you power down what's powering the relay then it should certainly stop buzzing the same as turning off the ignition. You would need a service manual and wiring diagram to tell if it makes pulling that fuse powered down the relay. You could also check power draw across the fuses to see which circuit is drawing power. If it's the start relay buzzing then I would check start switch first. It seems likely you have a short, but without really a logical place to start narrowing it down to a circuit is a start.

The relays themselves, the controlled circuit, bypasses the fuses. If you can't find anything out of the ordinary on the fuses then it might be one of those controlled circuits. You would have to check the current draw off the battery itself then pull the relays. It seems it would be a good idea to determine what's clicking under the faring. Hopefully that's gives you some direction to look in. Sorry about the relay, I should have said test it. Hopefully it didn't cost too much.

 

Well...a bro came over this afternoon with all his electronic gizmos and knowledge. He determined there was something drawing down the battery. We hooked up the battery charger. I told him the battery was just one year old! So after half an hour we tried the ignition switch. I HAD LIGHTS! But when I hit the starter, the lights dimmed and nothing happened. The buzzing happened because the battery was too weak to take the load! I was three weeks short of the one year warranty on the battery. We took it to where I bought it and they tested it and determined IT WAS BAD! A ONE YEAR OLD BATTERY WAS BAD! Unreal. But they replaced it and I'm runnin' again! Thanks for your help LilBudyWizer, I appreciate it! Don

 

I would have thought from the voltage that the battery was fine, but, perhaps, that just indicates how complete the charge and now how much juice it's actually holding.

 

glad you got yours going, but I have a similar issue.

I have a 79 sportster 1000 and the generator light kept staying on and killing the battery every year. So I just put on a brand new generator and battery and the generator light no longer goes on, everything was great, well today it died... I got it started and took it out on a high revving ride to try and charge it... it was even more dead after. but still no generator light?

 

The starting point would be checking that the voltage at the battery is higher while running than with no load. If it's lower while running then you're running off the battery. If you're higher then you're charging it.

 

I am guessing lower but I will check today. I am thinking either the reciprocater voltage regulator thing or starter are going.