The Neview 2351 fans connect to your motherboard through a standard three-pin or four-pin connector, depending on your motherboard's available headers
The Neview 2351 is a case fan designed to move air through your computer's chassis. It has a connector on its power cable that plugs directly into a fan header on your motherboard — a small socket usually labeled "SYS_FAN" (system fan), "CHA_FAN" (chassis fan), or "FAN" followed by a number. Your motherboard likely has between two and four of these headers available.
The connection is straightforward: you push the fan connector onto the pin header until it clicks or seats fully. The motherboard then powers the fan and, if it is a four-pin connector, allows the motherboard to control the fan's speed automatically based on temperature. A three-pin connector means the fan runs at full speed all the time.
Key Takeaways
- The Neview 2351 fan connector plugs into a fan header on your motherboard, usually labeled SYS_FAN, CHA_FAN, or FAN1, FAN2, and so on.
- A four-pin connector allows your motherboard to control fan speed automatically; a three-pin connector runs the fan at full speed.
- Push the connector straight onto the header pins until it seats fully, with the notch on the connector aligned to the key on the header.
- If your motherboard has no free fan headers, you can use a fan splitter cable or a separate power supply connector with a Molex-to-fan adapter.
- Check your motherboard manual to locate the fan headers and confirm whether they are three-pin or four-pin before connecting.
Locating the fan headers on your motherboard
Open your computer case and look at your motherboard. Fan headers are small rectangular sockets, usually arranged in a row or scattered across the board near the edges. They are typically labeled on the motherboard itself or in the manual. The most common locations are along the bottom edge, near the power connectors, or near the CPU socket.
Your motherboard manual will show you exactly where each header is and whether it is a three-pin or four-pin header. If you do not have the manual, you can search for your motherboard model number (usually printed on the board itself) plus "manual" online, and most manufacturers provide free PDFs. The manual will also tell you which headers the motherboard monitors for temperature control and which are straightforward power-only headers.
Understanding three-pin versus four-pin connectors
The Neview 2351 fan connector will be either three-pin or four-pin. A three-pin connector carries power only: ground, positive 12 volts, and a tachometer wire that reports the fan's speed back to the motherboard. The fan runs at full speed whenever power is on.
A four-pin connector adds a pulse-width modulation (PWM) wire that lets the motherboard slow the fan down by pulsing the power on and off very quickly. This keeps the fan quieter when your computer is cool and spins it faster only when needed. If your fan is four-pin and your motherboard has only three-pin headers, the fan will still work but will run at full speed — the extra pin straightforward will not connect.
How to plug the fan connector in correctly
Align the notch on the fan connector with the key (a small raised ridge or missing pin) on the motherboard header. The connector should slide on smoothly. Push it straight down until it seats fully — you should hear or feel a small click. Do not force it sideways or at an angle, as this can bend the pins inside the header.
The connector should sit flush against the header with no gap. If it does not slide on easily, check that the notch and key are aligned. If the header pins look bent or damaged, do not attempt to connect the fan — contact the motherboard manufacturer or consider replacing the header with a replacement part if you are comfortable soldering.
What to do if you have no free fan headers
If all your motherboard's fan headers are already in use, you have two options. The first is a fan splitter cable: a Y-shaped adapter that plugs into one header and allows you to connect two fans to it. Splitters are inexpensive and work well if you are not adding too many fans, though connecting more than two fans to a single header can overload it.
The second option is a Molex-to-fan adapter, which converts a four-pin Molex connector from your power supply into a fan connector. This bypasses the motherboard entirely and powers the fan directly from the power supply at full speed. Molex adapters are less common now but are useful if you want to add fans without using motherboard headers. Make sure the adapter is rated for the fan's power draw.
Checking that the fan is working after connection
Power on your computer and listen for the fan to spin up. You should hear it running within a few seconds. If the fan does not spin, power off when ready and check that the connector is fully seated on the header. Reseat it by gently pulling it straight off and pushing it back on.
If the fan still does not spin, the header itself may be faulty, or the fan may be defective. You can test this by connecting the fan to a different header if one is available. If it works on another header, the first header is bad. If it does not work on any header, the fan itself is likely defective and should be replaced.
Frequently Asked Questions
Can I connect a three-pin fan to a four-pin header?
Yes. The three-pin connector will plug into the first three pins of the four-pin header, and the fan will work normally. The fourth pin (PWM) will straightforward have nothing connected to it. The motherboard will not be able to control the fan's speed, so it will run at full speed.
What happens if I plug the connector in backwards?
The notch on the connector prevents you from plugging it in backwards — it will not fit. If you force it, you risk bending the pins inside the header. Always align the notch with the key before pushing the connector on.
Do I need to connect every fan to the motherboard, or can some fans just plug into the power supply?
You can do either. Fans connected to the motherboard can be monitored and controlled. Fans connected directly to the power supply (via a Molex adapter) run at full speed all the time. Most people connect case fans to the motherboard so the system can adjust speed based on temperature.
My motherboard manual says the header is "CPU_FAN" — can I connect a case fan there?
Technically yes, but it is not recommended. CPU_FAN headers are usually monitored more closely by the motherboard's safety systems, and connecting a case fan there may trigger false alarms or prevent the motherboard from detecting a problem with the actual CPU cooler. Use a SYS_FAN or CHA_FAN header instead.
How do I know if my fan header is working if the fan does not spin?
Try connecting a different fan to the same header. If the second fan spins, the header works and the first fan is faulty. If the second fan also does not spin, the header is likely bad. You can also check your motherboard's BIOS to see if the header is reporting any activity or errors.