this^^. This is a seriously old thread that someone bumped but since it’s here I’ll give a reminder to flush that brake fluid. Go ahead and rebuild the master cylinder and flush the fluid while you are there

 

Just bought my first bike 21 sportster 1200. This same situation just happened to me but different after owning it a full week and a half. Riding in second gear slow through the main strip after grabbing a bite all of a sudden the red light turned on and the bike just turned off. I quickly squeezed the clutch and coasted to a safe spot and backed it in, turned the ignition off and pulled the key. Of course I parked right in front of a street performer playing guitar with his amp and signing, just my luck. I quickly went on google and read somewhere that the red light went on someone’s bike just as someone else was saying their headlight was acting goofy. He put in on the high beam and rode home the whole way and the light went off. Then I found this thread, threw the key in, flipped on the bike, checked all the brake lights and signal lights all looked good, moved the back brake with my hand and squeezed the front, all was as it should. Red light was still on. I switched the high beam on and the red light remained on, I tried starting it and the bike came alive. I quickly shut it off, and did some more googling. Gave it 5 minutes and went back over, put the high beams on and bike started right up, red light gone, rode the whole way home with the Highbeams on no issues.

When I bought the bike the previous owner put in an adaptive LED headlight that has the sides go on when you turn left or right, I hated it cuz it was constantly flashing. I found it online for $500+ and was like shoot, might as well keep it. But after this incident I think I am ordering a normal LED light and taking this one out .

The red light is the security light according to the manual, but I don’t have a security system. Someone who has owned harleys for years says the alternator might be doing funky things, but why would the bike shut off while I was in gear cruising.

I know it’s an old thread but maybe someone has some new knowledge on this subject and can enlighten me on a fix?

 

This started after replacing my OEM headlight with an LED.
per Rufus Ai :When an LED headlight upgrade isn't recognized by your motorcycle's computer, it usually triggers warning lights because LED bulbs draw much less power than the original halogen bulbs. This is a common issue that can be easily fixed with the right load resistor or decoder.

Based on your Wisamic 5.75" LED Headlight, you'll need to add resistance to the circuit so your bike's computer recognizes the new LED as a "normal" headlight. Here are the solutions:

Motorcycle LED Load Resistors