How to replace motorcycle turn signal bulbs (step by step)

To replace motorcycle turn signal bulbs, remove the lens (usually held by one or two screws or a twist-off clip), press the old bulb in and turn it counterclockwise to release it, then push in a new bulb of the same type and turn it clockwise to lock. Refit the lens without overtightening the screws and test the signals. It's usually a 10-minute job with a screwdriver. The main things to get right are the bulb type and, on newer bikes, whether the signal even has a replaceable bulb.

Check whether your signals have bulbs

Many newer bikes use LED turn signals that are sealed units. Indian Motorcycle's Challenger owner's manual, for example, says its LED turn signals aren't serviceable, and a damaged or failed light requires replacing the entire assembly. If your signal is LED and has failed, the fix is a new signal unit, or a wiring repair if the problem is upstream. Our guide on motorcycle turn signals not working covers fuses, flasher relays and switches.

Bikes with incandescent signals, which include many cruisers, older bikes and budget models, have bulbs you can swap at home.

Identify the right bulb

Bulb	Filaments	Typical use
1156	One	Rear or front turn signal only
1157	Two	Front signals that double as running lights; brake/tail
67 / 1034 and others	Varies	Some older or smaller bikes
Wedge bulbs (e.g. 168, 194)	One	Smaller signals and indicator lights

The bulb code is usually stamped on the bulb's base. On many Harley-Davidson models, front and rear signals use different bulbs. Harley's instructions for its turn signal lens kits call for 1157A dual-filament bulbs in the front signals and 1156 single-filament bulbs in the rear on the models those kits fit. The "A" means amber.

Two-filament and single-filament bulbs have differently placed base pins, so one won't lock into the other's socket properly. Don't force it.

Clear lens vs amber bulb

If you have a clear or smoked lens, you need an amber bulb so the signal shows the right color. With an amber lens, a clear bulb is usually what the manual lists. Check before buying.

Tools and supplies

• Small Phillips or flat screwdriver (some lenses use hex screws)
• Replacement bulbs of the right code
• Dielectric grease (optional, a light film on the socket contacts)
• Clean rag
• Small pick or contact cleaner if the socket is corroded

How to replace motorcycle turn signal bulbs

1. Turn off the ignition

Switch the bike off. Bulbs can be hot if the signals were just in use.

2. Remove the lens

Look for screws on the lens face or underside. Some lenses pop off with a gentle pry at a notch, and some twist off. Harley-Davidson's lens kit instructions have you keep the original lens screws for reinstallation, which is good practice on any bike since the screws are often specific.

Handle the lens gently. Old plastic can be brittle, and the gasket behind it keeps water out.

3. Remove the old bulb

Most turn signal bulbs use a bayonet base: push the bulb in slightly, turn it counterclockwise, and pull it out. Wedge bulbs simply pull straight out.

4. Inspect the socket

Look for green or white corrosion, a loose socket, a melted area or a broken wire. Clean light corrosion with contact cleaner or a small brush. A badly corroded socket can cause dim or intermittent signals and is worth replacing.

5. Install the new bulb

Match the new bulb's pins to the slots in the socket, push in and turn clockwise until it locks. A light dab of dielectric grease on the contacts helps keep moisture out.

6. Test before refitting the lens

Turn the ignition on and test both left and right signals. If a front signal doubles as a running light, check both functions: the steady running light and the flash when you signal. Check the indicator on the dash too. If the headlight is also out, see how to replace a motorcycle headlight bulb.

7. Refit the lens

Seat the gasket, position the lens, and tighten the screws snugly but gently. Overtightening cracks lenses.

8. Check the flash rate

The MSF's T-CLOCS pre-ride checklist lists turn signals as needing to flash correctly. A normal rate is steady and not frantic. If one side flashes fast, see below.

Why a signal flashes fast after a bulb change

Cause	What to check
Wrong bulb wattage or type	Compare with the manual or the bulb on the other side
Bulb not fully seated	Remove and refit
Bad ground or corroded socket	Clean contacts, check the ground wire
Another bulb on that side is out	Check front and rear on the same side
LED bulb with an incandescent flasher	Fit an LED-compatible flasher or load resistors

Fast flashing with conventional bulbs often means another bulb on that side has failed. Check them all.

Common mistakes

• Buying by size instead of code. Two bulbs can look the same and still have different pin positions or wattage. Match the code stamped on the base.
• Forcing a bulb into the wrong socket. A dual-filament bulb in a single-filament socket can short or simply not work.
• Cracking the lens. Plastic lenses split if the screws are overtightened, and a cracked lens lets water in.
• Skipping the gasket. A missing or pinched gasket leads to moisture, corrosion and dead bulbs a few months later.
• Assuming the bulb is the problem. If a new bulb doesn't fix it, the cause may be the socket, ground, switch, fuse or flasher.
• Testing only one side. Check left and right, front and rear, and the dash indicator.

Front and rear signal differences

On many bikes the front and rear signals aren't identical. Front signals often double as running lights, which is why they take a two-filament bulb. Rear signals are usually signal only. Some bikes put the turn signal function into the taillight assembly instead of separate pods. Before you buy parts, pull one bulb from each end and compare.

Switching to LED bulbs

LED replacement bulbs use far less power. On bikes with a thermal flasher designed for incandescent bulbs, that can cause fast flashing or no flashing. The usual fixes are an LED-compatible flasher relay or load resistors. Load resistors get hot, so mount them away from plastic and wiring. Some bikes have the flasher function built into a body control module that needs a dealer setting. For more on LED lighting changes, see LED headlight bulbs for motorcycles.

Cost

Turn signal bulbs usually cost a few dollars each. A sealed LED signal assembly can cost much more. Shops may charge a small labor fee for a simple bulb swap and more for wiring or LED conversions. Costs vary by bike, region and shop.

When to see a mechanic

Get professional help if:

• New bulbs don't light up, or both signals on one side are dead
• The signals work intermittently, especially over bumps
• Fuses keep blowing
• The flash rate stays wrong after you've checked bulbs and grounds
• A factory LED signal has failed
• Wiring is damaged, chafed or melted

Turn signals are safety equipment. If they don't work, use hand signals and get them fixed promptly. Signals are part of every pre-ride inspection. Our motorcycle electrical repair page lists shops that handle lighting faults, and you can browse the motorcycle repair directory to find one near you.