Electronic Flasher Relay | Honda CB175 / CB200 / CB350 / CB360 / CB450 / CB500 / CB550 / CB750
If your turn signals stay on solid, flash erratically, or you are converting to LED bulbs — this electronic flasher relay is the fix. Unlike the OEM thermal flasher that depends on high current draw from incandescent bulbs, this solid-state relay works with both incandescent and LED turn signals. No load resistors needed.
Why You Need This
The original Honda thermal flasher relay uses a bimetallic strip heated by current flow to create the on-off flash pattern. It depends on the higher current draw of incandescent bulbs to generate enough heat to cycle. When you swap to LED turn signals — which draw far less current — the thermal flasher will not trigger. Your signals stay on solid or do not light at all.
This electronic relay uses a solid-state circuit with a low current threshold, so it flashes reliably with LED bulbs, incandescent bulbs, or a mix of both. It is a direct plug-in replacement for the OEM thermal relay — same two-terminal design, same wiring connector. If your original relay has simply failed from age, this electronic version is the upgrade path whether you are running LEDs or not.
Specifications
| Spec | Detail |
|---|
| Replaces OEM Parts | 38301-KJ6-743, 38300-292-670, 38301-KJ6-741, 38301-KJ6-742 |
| Fits Models | CB175 / CL175 / SL175 (1968–1973), CB200 / CL200 (1973–1976), CB350 / CL350 / SL350 (1968–1973), CB360 / CL360 / CJ360 (1974–1977), CB450 / CL450 (1965–1974), CB500T (1975–1976), CB500K (1971–1973), CB550K / CB550F (1974–1978), CB750 (1969–1978) |
| Voltage | 12V |
| Type | Solid-state electronic (low current threshold) |
| Terminals | Two spade: + (battery/12V positive) and – (load) |
| Compatibility | Works with incandescent bulbs, LED bulbs, or mixed |
| Sold As | Single unit |
Note: This relay is polarity-sensitive. If the turn signals turn on but do not flash, the wiring is reversed — swap the two connections. The black wire (12V+) goes to the + terminal, the gray wire goes to the – terminal.
Installation
Difficulty: Beginner
- Locate the flasher relay — on most models it is mounted under the seat near the battery or inside the headlight bucket.
- Pull the two-wire connector off the old relay and remove it from the mounting bracket.
- Connect the new relay: black wire (12V+) to the + terminal, gray wire to the – terminal.
- Turn the key on and test both turn signals.
Troubleshooting: If the signals turn on but do not flash, the relay is connected backwards — reverse the two wires. Also check your connectors for corrosion and inspect the left-hand control switch to make sure it is making good contact.
Our LED turn signal conversion video covers the complete wiring setup — including this electronic relay, the indicator diode, and how the turn signal circuit works with LED bulbs.
Frequently Asked Questions
Will this work with my stock incandescent turn signals?
Yes. This electronic relay works with incandescent bulbs, LED bulbs, or a mix of both. You do not have to convert to LED to use it — it is a direct upgrade from the OEM thermal flasher.
Do I need anything else to convert my turn signals to LED?
You need LED bulbs for the turn signals themselves, and if you are also converting the gauge-cluster turn signal indicator to LED, you will need our LED indicator diode to prevent cross-talk between the left and right circuits. The external turn signal conversion only requires this relay plus LED bulbs.
What is the difference between this and the OEM thermal flasher relay?
The OEM thermal flasher is current-based — it uses heat from the higher current draw of incandescent bulbs to trigger the flash cycle. It will not reliably flash LED bulbs because they draw too little current. This electronic relay uses a solid-state circuit that flashes regardless of current draw, so it works with any bulb type.
My turn signals stay on solid and do not flash. Is this relay bad?
If you just installed this relay and the signals stay on solid, it is likely connected backwards. This relay is polarity-sensitive — reverse the two wire connections. The + terminal goes to the black wire (12V positive) and the – terminal goes to the gray wire. If it still does not flash after reversing, check for corrosion at the connectors and make sure the left-hand switch is functioning.
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Last updated: March 2026
