Rear Lights
Year/model of bike, along with a pic or 2 of the components that you are describing will go a long way to getting resolution, especially if you cannot determine the parts to be OEM or aftermarket.
As of now, we don't know if this is regarding a factory tombstone light on a '48 or a Custom Dynamics LED light on a '23 CVO.
Nobody can help if they are guessing on the product in question.
Help us help you.
Year/model of bike, along with a pic or 2 of the components that you are describing will go a long way to getting resolution, especially if you cannot determine the parts to be OEM or aftermarket.
As of now, we don't know if this is regarding a factory tombstone light on a '48 or a Custom Dynamics LED light on a '23 CVO.
Nobody can help if they are guessing on the product in question.
Help us help you.
Your Indy is most likely correct in his assumption.
The part you referenced does not make the rear turn signals function as running lights or stop lights. It is just the circuit board that the various rear lights plug into, when they function as designed from the factory. I'm not saying there cannot be an issue with that part, but the fact that the rear turn signal in question functions at all, suggests that circuit board is fine. You should know how the OEM system works, so you can diagnose just what part(s) may be causing the problem. It will avoid possibly buying an unneeded part.
This is how the lights are designed to work:
The rear turn signals are single filament #1156 bulbs. They only work as flashing turn signals, with amber lenses from the factory.
The front turn signals are dual filament #1157 bulbs. They work as both running lights and flashing turn signals, with amber lenses from the factory.
To get the rear turn signals to act as all three; running lights, turn signals, and brake lights... You need to add a run/turn/brake module. The module plugs inline between two connectors, the connector for the main harness that plugs into the connector for the rear lights harness. That connection is under the seat, cam plate side, back by the rear fender. That module varies the voltage to the single filament rear turn signal bulbs, to allow them to function like dual filament bulbs.
If your rear turn signals were functioning as run/turn/brake, and now one is only functioning as turn and brake, the wiring has an issue, or the R/T/B module has failed.
I would find that connection and remove any module (HD accessory or aftermarket) plugged in between the two connectors mentioned.
If the lights return to how they are supposed to function from the factory, then the module has failed, time for a new module.
If the lights still have an issue, then I would investigate the wires, connectors, bulbs, sockets, etc., that are aft of that connection for an issue (ie: shorted wire, broken wire, bad connection, etc).
Good luck and report to us what you find....
Last edited by hattitude; Sep 14, 2024 at 05:16 PM.
Trending Topics
I didn't think this H-D run/brake/turn module was factory. My King certainly didn't come with it.
Last edited by RKZen; Sep 14, 2024 at 05:11 PM.
The Best of Harley-Davidson for Lifelong Riders
It is not on bikes from the factory.
It is from the Parts and Accessory Catalog, and is either dealer added or customer added after the bike is delivered from the factory......
Your Indy is most likely correct in his assumption.
The part you referenced does not make the rear turn signals function as running lights or stop lights. It is just the circuit board that the various rear lights plug into, when they function as designed from the factory. I'm not saying there cannot be an issue with that part, but the fact that the rear turn signal in question functions at all, suggests that circuit board is fine. You should know how the OEM system works, so you can diagnose just what part(s) may be causing the problem. It will avoid possibly buying an unneeded part.
This is how the lights are designed to work:
The rear turn signals are single filament #1156 bulbs. They only work as flashing turn signals, with amber lenses from the factory.
The front turn signals are dual filament #1157 bulbs. They work as both running lights and flashing turn signals, with amber lenses from the factory.
To get the rear turn signals to act as all three; running lights, turn signals, and brake lights... You need to add a run/turn/brake module. The module plugs inline between two connectors, the connector for the main harness that plugs into the connector for the rear lights harness. That connection is under the seat, cam plate side, back by the rear fender. That module varies the voltage to the single filament rear turn signal bulbs, to allow them to function like dual filament bulbs.
If your rear turn signals were functioning as run/turn/brake, and now one is only functioning as turn and brake, the wiring has an issue, or the R/T/B module has failed.
I would find that connection and remove any module (HD accessory or aftermarket) plugged in between the two connectors mentioned.
If the lights return to how they are supposed to function from the factory, then the module has failed, time for a new module.
If the lights still have an issue, then I would investigate the wires, connectors, bulbs, sockets, etc., that are aft of that connection for an issue (ie: shorted wire, broken wire, bad connection, etc).
Good luck and report to us what you find....












