Okay I will look into it , I'm guessing the bcm has a +12 input ?
I can try taping into that, do you know what the bcm looks like ?

 

It does. There are plenty of +12V powers around. You can even make your own with a fused link from the battery if all it needs is power to the alarm (this is what I would do, tapping in to BCM power can cause issues if it doesn't get smooth power). I was under the impression you needed a pulsed signal.

 

Thanks for all the feedback , I will experiment with it . That was very helpful

 

I totally missed it was a 2018, my apologies to the OP, didn't mean to send you on a wild goose chase

 

Sorry, I don't remember the correct way to post but I have a question about this subject.. Turn signal relays. I have a 2007 Sportster 1200 Low, 10500 miles. The turn signals stopped working. Both front turn signal lights stay lit. Headlight is on. Both turn signal lights are off in the rear. Back light is lit but brake light doesn't work. I checked all bulbs, checked for loose connections in the tail lights. all fuses are good. The only thing I can think of is the flasher or relay. I'm not sure if it actually has one or where it is. Any help would be appreciated. Thanks Pap1951

 

Turn signals and brake lights on different circuits, unless someone hacked in some kind of combination set up. Best to get a multimeter and start checking for power. Probably better to start a new thread as this one is old.

John

 

Your 2007 doesn't have a relay as such but a TSM or TSSM or even a HFSM

Wiring diagram - 99949-07_en_v1.1 - 2007 Wiring Diagrams | Harley-Davidson SIP

 

Domestic market bikes have running lights in the indicators. Which filament is on, the low power or high power?