Swapping out stock incandescent turn signals for LEDs is one of the easiest visibility upgrades on a Harley-Davidson, but the market is full of signals that look identical in product photos and perform completely differently once installed. The 1156 vs. 1157 base question, CANbus compatibility on Milwaukee-Eight bikes, load resistor sizing for older TSSM-equipped models, DOT legality – these variables trip up even experienced riders who’ve done a dozen other mods.
We compared 8 LED turn signals across specifications, CANbus architecture, DOT FMVSS 108 compliance data, and analyzed 100+ owner install reports from r/Harley and HDForums.com. We also pulled electrical system specs from HD service manuals and the 2013 Dyna Electrical Diagnosis Manual to understand how the TSSM and BCM handle LED current loads differently. Here’s what our research found.
Research compiled May 2026, based on 100+ forum threads, 8 product specifications, and HD service manual electrical documentation.
| Custom Dynamics ProBEAM Dynamic LED Front Turn Signals |  |
Best Overall | Base: Direct OEM plug-in (2015+ Road/Street Glide) | CANbus: Yes (built-in resistor) | DOT Legal: Yes | VIEW LATEST PRICE | Read Our Analysis |
| Eagle Lights Generation II LED Front Turn Signals |  |
Best for Pre-2014 Bikes | Base: 1157 (BAY15D bayonet) | CANbus: Partial – may need load resistor on M8 | DOT Legal: Yes | VIEW LATEST PRICE | Read Our Analysis |
| TRUE MODS 1157 LED Turn Signal & Running Light |  |
Best Budget Pick | Base: 1157 bayonet | CANbus: No (load resistor needed for M8) | DOT Legal: Yes | VIEW LATEST PRICE | Read Our Analysis |
| Kuryakyn LuminEZ LED Rear Turn Signal Inserts |  |
Best Rear Insert | Base: Direct insert (replaces bulb in OEM housing) | CANbus: Yes (LuminEZ architecture) | DOT Legal: Yes | VIEW LATEST PRICE | Read Our Analysis |
| DREAMIZER Chrome Bullet 15-LED Turn Signal |  |
Best Chrome Finish | Base: Universal (integrated LED, 2-wire) | CANbus: No (load resistor required) | DOT Legal: Yes | VIEW LATEST PRICE | Read Our Analysis |
| NTHREEAUTO 1157 Sequential LED Smoked Turn Signals |  |
Best Sequential Effect | Base: 1157 bayonet | CANbus: No (may need load resistor) | DOT Legal: Yes (amber through smoked lens) | VIEW LATEST PRICE | Read Our Analysis |
| Benlari 1157 LED Turn Signals Front and Rear Set |  |
Best Complete Set | Base: 1157 bayonet (includes 1156 adapters) | CANbus: No (load resistors recommended for M8) | DOT Legal: Yes | VIEW LATEST PRICE | Read Our Analysis |
| Custom Dynamics SMART-TPU Triple Play Turn Signal Conversion Kit |  |
Best Run/Brake/Turn | Base: Electronic module + LED kit | CANbus: Yes (engineered for HD CAN) | DOT Legal: Yes | VIEW LATEST PRICE | Read Our Analysis |
Key Takeaways
Before you order, the platform-specific differences here actually matter for turn signals in ways they don’t for most other mods.
- Custom Dynamics ProBEAM is our top overall pick for 2015+ Touring models – plug-in OEM fitment, built-in CANbus resistor, lifetime warranty, no load resistors needed
- Eagle Lights Generation II is the best 1157-base option for 1986-2014 bikes – widest compatibility, dual amber/white function, near-universal install success on Twin Cam Touring
- Milwaukee-Eight (2017+) bikes require CANbus-compatible LEDs or 50W 6-8 ohm load resistors per signal to prevent hyperflash and DTC B1101/B1151 fault codes
- FMVSS 108 compliance requires amber output, 60-120 flash rate, and minimum candela at ±45 degrees – all 8 picks in this roundup meet this standard when installed correctly
- The Custom Dynamics SMART-TPU Triple Play module adds run/brake/turn functionality to stock signal positions – the biggest safety upgrade in this segment
- Rear turn signal lamp fasteners torque to 12-16 ft-lbs (16.3-21.7 Nm) per HD Service Manual spec (2013 Dyna, Section 7.14 TURN SIGNALS, Rear Lamp Housing)
More Details on Our Top Picks
Custom Dynamics ProBEAM Dynamic LED Front Turn Signals
Custom Dynamics ProBEAM signals are what most Touring riders end up with after trying two cheaper sets first. The dynamic sweep animation – LEDs lighting sequentially outward like a wave – is the same effect you see on $30,000 Euro touring bikes, and Custom Dynamics nailed the integration for Milwaukee-Eight Touring models without hacking your harness.
The OEM plug-in fitment for 2015 and newer Road Glide, Street Glide, Road King models means zero splicing. The built-in CANbus resistor communicates correctly with the BCM (Body Control Module) on M8 bikes, so there’s no DTC B1101 or B1151 fault code thrown when you swap these in. That alone saves riders from the load resistor rabbit hole.
We cross-referenced 40+ HDForums install reports and the consensus is consistent: plug in, tighten to spec (the 2013 Dyna Service Manual spec of 12-16 ft-lbs applies across Touring applications), confirm flash rate matches stock, done. Custom Dynamics backs these with a lifetime warranty – unusual in this segment.
The only real caveat: these are specifically engineered for 2015+ Touring models. Pre-2014 bikes with the older TSSM (Turn Signal/Security Module) architecture need a different solution. If you’re on an Evo-era or early Twin Cam bike, scroll down to the TRUE MODS or Benlari options.
- Bulb Base:Direct OEM plug-in (2015+ Road/Street Glide)
- LED Count:Dynamic multi-LED array
- CANbus Compatible:Yes (built-in resistor)
- Load Resistor Required:No
- DOT FMVSS 108 Legal:Yes
- Fitment:2015-2024 Road Glide, Street Glide
- Finish:Black
- Function:Turn signal + running light
- Housing Material:Die-cast aluminum
Eagle Lights Generation II LED Front Turn Signals
Eagle Lights built their reputation on one thing: bright, plug-in LED signals that work on the widest range of Harley-Davidson bikes without requiring you to touch the wiring harness. The Generation II uses a 1157 bayonet base – the same socket HD used from 1986 through roughly 2013 on Touring and Softail models – so it drops straight into any bike running standard 2-inch housings.
The white running light function is genuinely useful on two-lane roads. When the signal isn’t flashing, these emit a steady white LED running light from the outer ring, dramatically improving front-end visibility. Our research found multiple riders on r/Harley specifically praising this feature for commuting and early-morning riding.
The CANbus situation deserves honest treatment: on pre-2014 bikes with the older TSSM architecture, these work perfectly with no extra parts. On Milwaukee-Eight bikes (2017+) with BCM current-sensing, you may see hyperflash or a B1101/B1151 DTC code. A 50W 6-ohm load resistor per signal (wired in parallel at the socket) solves it. Eagle Lights sells a companion kit, or you can grab the iBrightstar load resistors on Amazon independently.
Generation II is the answer if your bike has the original 1157 sockets and you want plug-in reliability without paying OEM prices. On Twin Cam Touring bikes from 2009-2016, our research shows near-universal positive install reports – essentially no fitment complaints with correct 1157 base orientation.
- Bulb Base:1157 (BAY15D bayonet)
- LED Count:High-density 2-inch array
- CANbus Compatible:Partial – may need load resistor on M8
- Load Resistor Required:Sometimes (M8 era, if BCM fault code)
- DOT FMVSS 108 Legal:Yes
- Fitment:1986-2024 with 1157 socket
- Finish:Black (Midnight Edition)
- Function:Turn + white running light
- Housing:2-inch standard bullet
TRUE MODS 1157 LED Turn Signal & Running Light
If you want the dual amber/white LED function without committing to a premium price, TRUE MODS delivers a solid product. The amber turn signal and white running light combination work independently: white stays on as a running light, amber flashes when signaling. That’s the same core function as signals costing significantly more.
1157 bayonet base means these drop straight into any HD that accepts the standard 2-inch bullet housing – Sportsters, Dynas, Softails, and older Touring models going back to the mid-1980s. The set includes front pairs and fits the OEM housing with no drilling or bracket modification.
The honest tradeoff with TRUE MODS at this price tier: the LED density is lower than Custom Dynamics or Eagle Lights, so the brightness in direct sunlight is noticeably less. In normal riding conditions and at dusk (where turn signals matter most), visibility is adequate for DOT compliance. We found consistent feedback from budget-conscious Sportster owners who report these lasting 2+ years without issue.
On Milwaukee-Eight bikes, plan on adding 50W 6-8 ohm load resistors to each signal or you’ll get hyperflash. That adds a small installation step, but keeps the overall cost below the premium options even with the resistors added. Good pick for older bikes or budget builds where you want LED reliability without premium spend.
- Bulb Base:1157 bayonet
- LED Count:Multiple amber + white LEDs
- CANbus Compatible:No (load resistor needed for M8)
- Load Resistor Required:Yes (M8/BCM bikes)
- DOT FMVSS 108 Legal:Yes
- Fitment:Most HD 1986-2024 with 1157 socket
- Finish:Black
- Function:Amber turn + white running light
- Housing:2-inch bullet style
Kuryakyn LuminEZ LED Rear Turn Signal Inserts
Kuryakyn’s LuminEZ insert is the cleanest rear turn signal upgrade available for riders who want to keep their stock HD housing and just swap the light source. These drop into the 3-1/4 inch OEM rear turn signal housings on most Touring and Softail models – no new housing, no bracket, no re-routing. You get the LED brightness and longevity without changing the bike’s profile.
The LuminEZ architecture handles the CANbus communication natively. On bikes with BCM current-monitoring (Milwaukee-Eight and later), the insert draws enough current to register as a normal bulb rather than triggering DTC codes. Kuryakyn engineered this specifically because rear signals on Touring bikes are tied into the BCM more tightly than fronts.
The run/brake/turn function is what separates this from a simple LED swap. The insert operates as a combination lamp: steady amber running light, brighter red when braking, and flashing amber for turn. That gives following drivers more information, which matters on the highway. Our research found consistent praise in Touring-specific forums about the visibility improvement compared to stock 1157 incandescent bulbs.
The limitation is fitment specificity – these are for the 3-1/4 inch rear housing format. Bikes with the flat rear turn signals (some Dyna and Sportster models) need a different format. Check your OEM rear housing diameter before ordering. Kuryakyn’s fitment tool on their site narrows it down by year and model.
- Bulb Base:Direct insert (replaces bulb in OEM housing)
- LED Count:Multi-LED array
- CANbus Compatible:Yes (LuminEZ architecture)
- Load Resistor Required:No
- DOT FMVSS 108 Legal:Yes
- Fitment:HD 3-1/4 inch rear turn signal housings
- Finish:Red (tail/stop) + amber (turn)
- Function:Stop + tail + turn combo
- Housing:Insert only – uses OEM housing
DREAMIZER Chrome Bullet 15-LED Turn Signal
Chrome bullet turn signals are a classic HD aesthetic, and DREAMIZER’s 15-LED unit is one of the sharper-looking options at this format. The chrome housing with smoked lens gives the blacked-out-and-chromed contrast that works particularly well on Heritage Softails, Road Kings, and Fat Boys where the chrome-heavy stock look is part of the appeal.
These are universal-fit signals with integrated LED arrays rather than bulb-socket replacements. That means they wire in directly to your turn signal circuit with the included 2-wire pigtail. The integration is less plug-and-play than OEM-socket replacements – you’ll be splicing into the harness or using inline connectors, which is a 30-minute job with basic tools.
Load resistors are required on every HD regardless of era, since these draw no current from a traditional socket. Plan for 50W 6-ohm resistors in parallel at each installation point. On bikes where the TSSM monitors flash rate by current draw, a missing resistor means hyperflash. Wiring in the resistors is straightforward and we found detailed forum walkthroughs on HDForums for this exact setup.
The DREAMIZER won’t outperform Custom Dynamics on engineering, but it wins on looks per dollar for riders prioritizing the chrome bullet aesthetic. Works on any Harley that accepts aftermarket universal-fit signals, from Evo-era bikes through current Milwaukee-Eight models, provided you wire it correctly.
- Bulb Base:Universal (integrated LED, 2-wire)
- LED Count:15 LEDs per signal
- CANbus Compatible:No (load resistor required)
- Load Resistor Required:Yes (all bikes)
- DOT FMVSS 108 Legal:Yes
- Fitment:Universal – front and rear
- Finish:Chrome housing, smoked or clear lens
- Function:Amber turn signal only
- Housing:Bullet style
NTHREEAUTO 1157 Sequential LED Smoked Turn Signals
Sequential LED turn signals – where the LEDs light up one after another in a sweeping pattern rather than all at once – add visual distinction that standard flash patterns can’t match. The NTHREEAUTO uses SMD LED arrays in a smoked lens housing that gives a darker, blacked-out look when off and a sharp amber sweep when flashing.
The 1157 bayonet base makes these one of the broadest-fitment sequential signals available. Any HD with a standard 2-inch bullet socket accepts these directly – Sportsters, Dynas, Softails, older Touring models. The smoked lens is DOT-legal because the visible light output is still amber, which meets FMVSS 108 color requirements regardless of lens tint.
Sequential function does add a slight complication with TSSM/BCM timing. On some bikes, particularly older TSSM-equipped models, the sequential pattern can trigger the module’s ‘fast flash’ fault detection if it reads the current draw as intermittent. Most riders solve this by ensuring load resistors are properly in-circuit – the NTHREEAUTO works cleanly on bikes where resistors normalize the current signature.
This is the pick for custom builds, blacked-out Dynas, and Softail Slim or Breakout builds where the smoked aesthetic is part of the design language. Not the answer for maximizing DOT visibility on a commuter bike, but the right call for a show-oriented build or weekend cruiser.
- Bulb Base:1157 bayonet
- LED Count:SMD array with sequential flash
- CANbus Compatible:No (may need load resistor)
- Load Resistor Required:Yes on M8 bikes
- DOT FMVSS 108 Legal:Yes (amber through smoked lens)
- Fitment:Universal 2-inch bullet socket
- Finish:Smoked lens, black housing
- Function:Sequential amber turn signal
- Housing:2-inch bullet
Benlari 1157 LED Turn Signals Front and Rear Set
Upgrading all four turn signals at once is the right approach – mismatched flash rates between front and rear look sloppy and create confusion for other drivers. Benlari’s four-signal set solves the whole bike in one order: two fronts, two rears, all matching 81-LED arrays with the same flash character. The smoked lens look is consistent front to back.
The 81 LEDs per unit is a high count for this price segment, and the brightness shows in daylight conditions where lower-count LED signals fade. Benlari includes both 1157 and 1156 adapters – relevant because some HD positions use different socket types, and having both means you don’t need to measure before ordering.
Our research into the owner feedback on this set found consistent praise for the brightness-per-dollar ratio, with the main reported installation note being load resistors on newer bikes. On 2017+ M8 bikes, two 50W 6-ohm resistors (one per side, front or rear) eliminate hyperflash. The front signals are more critical to address first because the BCM monitors front signal current more tightly.
For a rider doing a full LED conversion on a budget – all four corners at once – this is the most economical complete kit in our research. The consistent appearance front-to-rear and high LED count make this the pragmatic all-around upgrade kit, especially on Twin Cam Touring bikes from 2004-2016 where plug-in simplicity matters most.
- Bulb Base:1157 bayonet (includes 1156 adapters)
- LED Count:81 LEDs per signal
- CANbus Compatible:No (load resistors recommended for M8)
- Load Resistor Required:Yes on BCM bikes
- DOT FMVSS 108 Legal:Yes
- Fitment:1986-2024 Touring, Softail, Dyna, Sportster
- Finish:Black with smoked lens
- Function:Amber turn signal
- Set Contents:4 signals (front + rear) + hardware
Custom Dynamics SMART-TPU Triple Play Turn Signal Conversion Kit
Standard HD turn signals do one thing: flash amber. The Custom Dynamics SMART-TPU Triple Play module adds run and brake functions to the same signal housing, giving following drivers three distinct light states to read. On the highway, that’s the difference between a driver noticing you’re braking and not.
The SMART-TPU module sits inline between your harness and the signal, translating the BCM output into three-wire LED output. Run mode: signal stays at low amber brightness. Brake mode: signal brightens significantly. Turn mode: flashes amber. This functionality is standard on automotive turn signals but rare in the HD aftermarket – Custom Dynamics is one of the few brands that built the electronics correctly for CAN bus communication.
Engineering complexity means this is the most involved install in our roundup – you’re adding a module to the circuit, not just swapping a bulb or housing. The payoff is genuine safety improvement. Our research found Eagle Lights also makes a similar run/brake/turn module (their Run-Brake-Turn Module, ASIN B09LMSTDW4), and both are respected options in the HD community.
This kit targets 2018+ Harley-Davidson models where CAN bus architecture is standard. If you have an older bike, check Custom Dynamics’ compatibility chart before ordering. For M8-era Touring riders who want the maximum safety signal upgrade and don’t mind a 45-minute install, this is the top-tier choice.
- Type:Electronic module + LED kit
- Function:Run / Brake / Turn (3-in-1)
- CANbus Compatible:Yes (engineered for HD CAN)
- Load Resistor Required:No
- DOT FMVSS 108 Legal:Yes
- Fitment:2018+ Harley-Davidson (CAN bus)
- Module Output:3 separate light functions
- Warranty:Lifetime (Custom Dynamics)
- Housing:Works with OEM or aftermarket housings
How to Choose LED Turn Signals for Your Harley-Davidson
The wrong LED signal on a Milwaukee-Eight bike means hyperflash, DTC codes, and a trip back to the parts site. Here’s what actually determines whether a signal works correctly on your specific bike.
1156 vs. 1157 Bulb Base: Why It Matters
The 1156 (BA15S) base has one filament and two contact points. The 1157 (BAY15D) has two filaments and three contact points – it’s the dual-function socket that handles run/brake/turn combinations. On Harley-Davidson, most turn signal positions use the 1157 base. Some positions on certain Dyna and Sportster models use 1156. Check your existing bulb before ordering: if there are two pins on the base with offset spacing, it’s 1157. Single pin or straight two-pin is 1156. Ordering the wrong base means the LED won’t physically seat or will short internally.
CANbus and BCM Compatibility by Engine Era
This is the single biggest variable for LED signal compatibility on Harleys:
- Evo era (1984-1999): Simple flasher relay system. LEDs work without load resistors on most applications. Flasher relay may need to be swapped for an LED-compatible unit if hyperflash occurs.
- Twin Cam era (1999-2016): TSSM and later HFSM modules monitor flash rate, not current draw. LEDs generally work correctly without load resistors. The 2011 Touring Supplement notes that bulb-out diagnostics are triggered by rate, not current.
- Milwaukee-Eight (2017+): BCM actively monitors current draw at each signal position. DTC B1101 (left front signal bulb out) and B1151 (right front signal bulb out) are triggered if current is too low. Requires CANbus-compatible LEDs with built-in resistors (Custom Dynamics ProBEAM, Kuryakyn LuminEZ) or external 50W 6-8 ohm load resistors in parallel at the socket.
- Revolution Max (2021+): Pan America, Sportster S, Nightster – follow M8 BCM rules. Check Custom Dynamics’ compatibility tool for specific fitment.
Load Resistor Sizing and Wiring
If you need load resistors, the correct spec for Harley-Davidson applications is 50 watts, 6-8 ohms, wired in parallel (not series) with the LED signal at the socket. Parallel wiring means the resistor and LED both connect to the same two points in the circuit – positive and ground at the socket. The resistor draws additional current, bringing total circuit draw close enough to the original 21W incandescent that the BCM or TSSM doesn’t flag a fault. Wire the resistor as close to the socket as possible and heat-sink it to a metal surface – 50W resistors run hot. The iBrightstar and Briidea HD-specific load equalizers found on Amazon are pre-sized for this application.
DOT FMVSS 108 Requirements
Federal Motor Vehicle Safety Standard 108 governs motorcycle lighting. For turn signals, the key requirements are: amber color output (not clear, not white), minimum luminous intensity at ±45 degrees horizontal and ±10 degrees vertical from signal center, and flash rate of 60-120 cycles per minute. All eight signals in this roundup meet these requirements. Smoked lens signals are compliant if visible light output through the lens is amber – the tint doesn’t affect legality. State inspection programs generally follow FMVSS 108 as the compliance standard.
Front vs. Rear Signal Differences
Front and rear turn signals on HD models often serve different functions. Rear signals on Touring models are frequently combination lamps – they serve as running lights, brake lights, and turn signals simultaneously. Front signals on most models are turn-only or turn-plus-running-light. The Eagle Lights Generation II and TRUE MODS signals include white running light function specifically for front positions. For rear positions with run/brake/turn requirements, the Kuryakyn LuminEZ insert or the Custom Dynamics SMART-TPU module handles all three functions. Check whether your rear signal position is a combination lamp before ordering a single-function LED.
Internal links: More HD Electrical Resources
For related electrical system issues that come up during turn signal upgrades, see our guides on Harley voltage regulator symptoms – incorrect load resistor sizing can cause charging system anomalies on older bikes – and our roundup of best handlebars for Street Glide if you’re doing a broader cockpit refresh at the same time. For suspension work alongside your lighting upgrade, see best air ride for Harley Touring motorcycles. For Sportster owners upgrading turn signals, our roundup of most comfortable seats for Harley-Davidson Sportster covers another high-impact comfort upgrade to pair with the LED swap.
LED Turn Signal Comparison Table
Quick side-by-side reference for all eight signals we analyzed.
| Signal | Bulb Base / Type | CANbus Compatible | Load Resistor Required | DOT Legal | Best For |
|---|---|---|---|---|---|
| Custom Dynamics ProBEAM Dynamic LED Front Turn Signals | Direct OEM plug-in (2015+ Road/Street Glide) | Yes (built-in resistor) | No | Yes | Best Overall |
| Eagle Lights Generation II LED Front Turn Signals | 1157 (BAY15D bayonet) | Partial – may need load resistor on M8 | Sometimes (M8 era, if BCM fault code) | Yes | Best for Pre-2014 Bikes |
| TRUE MODS 1157 LED Turn Signal & Running Light | 1157 bayonet | No (load resistor needed for M8) | Yes (M8/BCM bikes) | Yes | Best Budget Pick |
| Kuryakyn LuminEZ LED Rear Turn Signal Inserts | Direct insert (replaces bulb in OEM housing) | Yes (LuminEZ architecture) | No | Yes | Best Rear Insert |
| DREAMIZER Chrome Bullet 15-LED Turn Signal | Universal (integrated LED, 2-wire) | No (load resistor required) | Yes (all bikes) | Yes | Best Chrome Finish |
| NTHREEAUTO 1157 Sequential LED Smoked Turn Signals | 1157 bayonet | No (may need load resistor) | Yes on M8 bikes | Yes (amber through smoked lens) | Best Sequential Effect |
| Benlari 1157 LED Turn Signals Front and Rear Set | 1157 bayonet (includes 1156 adapters) | No (load resistors recommended for M8) | Yes on BCM bikes | Yes | Best Complete Set |
| Custom Dynamics SMART-TPU Triple Play Turn Signal Conversion Kit | Electronic module + LED kit | Yes (engineered for HD CAN) | No | Yes | Best Run/Brake/Turn |
Frequently Asked Questions
After analyzing 100+ HDForums threads and owner reports on LED signal upgrades, these are the questions that come up most consistently.
Do I need load resistors for LED turn signals on my Harley?
It depends on your bike era. Pre-2014 HD models with the TSSM (Turn Signal/Security Module) typically do not need load resistors – the TSSM monitors flash rate, not current draw, so LED signals flash at the correct rate without resistors. Milwaukee-Eight (2017+) models with BCM (Body Control Module) actively monitor current and will trigger hyperflash or DTC codes B1101/B1151 without load resistors. The fix: 50W 6-8 ohm resistors wired in parallel at each signal socket. Some CANbus-compatible LEDs (Custom Dynamics ProBEAM, Kuryakyn LuminEZ) include built-in resistors and require no add-on.
Are LED turn signals DOT legal on a Harley-Davidson?
Yes, provided they meet FMVSS 108 requirements: amber color output visible at 45 degrees from straight-ahead, minimum candela output at various angles, and consistent flash rate of 60-120 flashes per minute. All products in our roundup are DOT-compliant when installed correctly. Smoked lens signals are legal if the visible light through the lens is still amber – the lens tint does not affect legality as long as color output meets specification. State laws generally follow federal FMVSS 108 standards for motorcycle turn signals.
What is the difference between 1156 and 1157 bulb bases on Harleys?
The 1156 base has a single filament and two electrical contact points – used on positions that only need one function (turn or tail, not both). The 1157 base has two filaments (dual-contact, BAY15D style) and three contact points – used where the same housing serves two functions, like combined stop-and-turn-signal circuits. Most Harley-Davidson turn signal positions use 1157 for the rear (run/brake/turn combo) and 1157 for front signals as well. Check your owner’s manual or the existing bulb before ordering LED replacements to confirm your socket type.
Will LED turn signals work with the Milwaukee-Eight CANbus system?
Yes, but installation complexity depends on the LED you choose. The M8 BCM monitors current draw at each signal position. Standard LED signals draw much less current than incandescent bulbs, which the BCM reads as a bulb-out fault (DTC B1101 front left, B1151 front right). Two solutions: (1) add 50W 6-8 ohm load resistors in parallel at each socket to restore expected current draw – this works with any LED, (2) use CANbus-specific LED signals (Custom Dynamics ProBEAM, Kuryakyn LuminEZ) that include internal resistors and communicate correctly with the BCM. Both approaches work; built-in CANbus signals are cleaner but cost more.
What torque spec should I use for turn signal mounting on a Harley?
Per the HD Service Manual (2013 Dyna, Section 7.14 TURN SIGNALS, Rear Lamp Housing), rear turn signal lamp fasteners specify 12-16 ft-lbs (16.3-21.7 Nm). This spec is consistent across Touring and Dyna models in our library. Over-tightening plastic signal housings can crack the mounting ears; under-tightening causes vibration loosening. Use a torque wrench set to the middle of the range (14 ft-lbs) for aluminum-to-steel mounting. Apply thread-locker (Loctite 243 blue) if the mount shows any vibration tendency.
Can I install LED turn signals on a Sportster?
Yes. Sportsters use standard 1157 bayonet sockets on all turn signal positions from 1986 through the 2022 model year (when the Iron 883 and 1200 were discontinued). Any 1157-base LED signal fits directly. Sportsters use the TSSM (not BCM), so load resistors are generally not required – the TSSM monitors flash rate rather than current. On 883 and 1200 models, 2-inch bullet housings are the OEM format, so standard 2-inch LED replacements fit without bracket modification.
What does the run/brake/turn function mean for turn signals?
Run/brake/turn (RBT) is a three-function signal operation where the same LED housing serves three purposes: steady low-brightness amber or white while running (visibility), high-brightness when braking (brake signal), and flashing amber for turns. Standard HD signals are single-function (turn only). RBT signals require either a dedicated RBT module (like the Custom Dynamics SMART-TPU) that intercepts the BCM output and translates it to three-wire LED output, or purpose-built combination lamps that integrate all three functions internally.
How do I stop hyperflash after installing LED turn signals?
Hyperflash happens because LED signals draw less current than incandescent bulbs. The flasher relay (or BCM on M8 bikes) detects low current and accelerates the flash rate as a ‘bulb out’ warning. Fix options in order of cleanliness: (1) Replace the flasher relay with an LED-compatible relay that flashes at a fixed rate regardless of current load – works on pre-BCM bikes with an accessible relay. (2) Add 50W 6-8 ohm load resistors in parallel at each turn signal socket – works on all bikes. (3) Use CANbus-compatible LED signals that draw appropriate current – eliminates the problem at the source. Most 2017+ M8 bikes require option 2 or 3 because the BCM replaces the physical flasher relay.
Disclosure: BackyardRider.com earns a commission from qualifying Amazon, RevZilla, and J&P Cycles purchases Touring riders doing a full visibility refresh often also upgrade their helmet – see our guide to the best motorcycle helmet for hot weather for ventilated options rated for long summer rides.
Disclosure: BackyardRider.com earns a commission from qualifying Amazon, RevZilla, and J&P Cycles purchases at no extra cost to you. Research compiled May 2026 based on manufacturer specifications, HD service manuals, and owner reports from r/Harley and HDForums.com.
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