When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I installed the Harley Speedometer Tachometer several years ago, and I love it. I'm trying to find out what the 2 lights (red and yellow) that come on when you turn the ignition switch on are for. Those lights go out after a few seconds, something about the o2 sensor setting or something like that. Anybody help? Specifically the ones under the tach.
Last edited by dustyinfla; Feb 22, 2026 at 03:01 PM.
The red circular light is the security system light. If you have a security system on the bike, that light will flash on and off every few seconds when security is armed and the ignition is off. It will also light and stay lit if you have active diagnostic trouble codes (DTC).
The yellow or amber light on the right is your check engine light.
It is normal for both of them to illuminate for a few seconds and then go out when the ignition is turned on.
Slideshow: Jason Momoa's latest restoration project blends 1920s Harley-Davidsons with modern electric technology, creating some of the most unusual hybrid motorcycles ever built.
Harley-Davidson Fat Boy Becomes a Dark, Decepticon-Inspired Custom
Slideshow: Killer Custom's latest build relies on styling changes rather than performance upgrades, giving the cruiser an entirely different personality.
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Slideshow: The bar-and-shield logo shows up on far more than motorcycles, some of the company's most unexpected products have nothing to do with riding.
Slideshow: From the troubled AMF years to modern misfires, these bikes earned reputations for reliability issues, questionable engineering, or disappointing performance.
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Slideshow: The Swiss custom shop has taken a Harley Softail and stretched it into something so long and low that it looks closer to a rolling sculpture than a conventional motorcycle.
Harley Speedometer Tachometer
