4-Pin PWM Fan Splitter Cable 10.5 Inch 1-to-2 Converter

Description

The 4-Pin PWM Fan Splitter Cable is a 10.5-inch 1-to-2 adapter that connects two cooling fans to one standard 4-pin PWM host header. It is suited to push-pull heatsinks, dual-fan Bitcoin miner upgrades, PC cooling, and server builds where both fans should follow the same PWM control signal.

The master branch carries power, PWM, and tachometer feedback. The slave branch carries power and PWM but intentionally omits the tachometer return, preventing two RPM signals from colliding on one host input.

4-Pin PWM Fan Splitter Specifications

Master and Slave Fan Outputs

Connect the fan you want AxeOS, BIOS, or another controller to monitor to the master branch. Both fans receive the same PWM duty-cycle command, but only the master returns RPM. The slave’s missing tachometer pin is intentional and is not a defect.

The two fans do not have to report identical RPM. Even matching models can vary slightly, while different models may respond very differently to the same PWM command.

Header Current and Voltage Compatibility

This splitter is passive, so the host header powers both fans. Add both fans’ rated running current, account for startup current, and confirm the total remains below the host board’s fan-header limit. If the combined load is too high, use a separately powered fan hub rather than drawing more current through the header.

The cable can pass 5V or 12V from a compatible host, but every connected fan must match that supplied voltage. No 24V compatibility is claimed. Physical connector fit does not prove voltage compatibility.

3-Pin and 4-Pin Fan Behavior

Four-pin PWM fans receive power, tachometer monitoring on the master branch, and a PWM control signal. A standard 3-pin fan can connect mechanically but cannot use the fourth-wire PWM signal, so its speed behavior depends on the host and may default to full supplied voltage.

This cable does not carry RGB or ARGB lighting signals. Fans with lighting require their separate lighting connector and a compatible controller.

Installation

1. Shut down and unplug the host device.
2. Confirm the host-header voltage and current rating.
3. Confirm both fans match the supplied voltage and combined current limit.
4. Connect the splitter input to the host’s 4-pin PWM fan header.
5. Connect the monitored fan to the master branch.
6. Connect the second fan to the slave branch.
7. Route the braided cable away from fan blades, heatsinks, and sharp edges.
8. Power on and monitor RPM, component temperature, and fan operation before increasing load.

What’s Included

• 1 × black braided 10.5-inch 4-pin PWM 1-to-2 fan splitter cable