The green neutral light helps the rider when the ATV is in neutral. One of the more common issues ATV owners run into is when the neutral light suddenly will no longer turn on.
When this happens, there are several potential causes, most of which are relatively easy to fix except when there is an issue with the transmission internals.
When the neutral light on an ATV doesn’t come on, it’s usually an electrical issue, such as a faulty or stuck neutral safety switch, loose connector, or bad wiring. Other less common causes include a blown fuse, a defective light bulb, or a mechanical transmission issue.
We’ll also look at a few less likely causes that may be worth looking into if the more common ones check out.
As a bonus, many of the same principles apply when the green reverse gear indicator light doesn’t come on.
What Is the Purpose of the Neutral Indicator Light?
Finding neutral can be a bit fiddly, particularly on ATVs with a manual transmission and a foot lever to change gears. When the neutral light turns green, the rider knows it’s safe to release the clutch without the bike taking off.
However, the neutral light is not only there to make it easier to find neutral. It’s also an important safety feature that prevents the accidental starting of the ATV in gear. If an adult forgets to check if the bike is in neutral or a child accidentally starts the vehicle, at least it won’t suddenly take off.
That is why, on most ATVs, the gear shifter needs to be in neutral (or park), or the engine will not crank when activating the starter. The only exception is some manual models where the bike starts in gear as long as you press the handlebar clutch lever.
How the Neutral Light and Neutral Safety Switch Work
The way a neutral light works on an ATV is quite simple:
- Constant Power Supply: When the key is turned on, the neutral light receives a continuous 12V current from the battery.
- Path to Ground: This current needs a ground connection for the light to illuminate. The bulb connects to ground through the neutral safety switch, typically on the ATV’s transmission.
- Neutral Position Activation: When the transmission is in neutral, the switch creates a ground path through the engine block. This causes the neutral light to turn on. Simultaneously, a signal is sent to the Engine Control Module (ECM) or a starter relay, indicating that it’s safe to start the ATV. This activates the starter solenoid, which then powers the electric starter.
- Non-Neutral Position: When the transmission is not in neutral, the neutral safety switch interrupts the ground path, so the neutral light turns off. In this state, the ECM or starter relay doesn’t receive a signal from the switch, preventing power from being directed to the starter solenoid. This means the ATV won’t start unless it’s in neutral.
Here is a simplified wiring diagram of how the neutral light and neutral safety switch are connected.
The switch is mechanically attached to a small shaft from the transmission. When you shift gears, the axle turns, and the switch shifts accordingly.
The specific design of the switch varies. Some ATVs have a plunger-style switch that shifts in and out, some have an axle with a small pin that rotates, and others have a plastic shim with a bare spot in the neutral position.
But they all serve the same purpose: to ground out the ignition switch circuit. More specifically, for the neutral light to turn on, the switch must make a path to ground when the bike is in neutral.
The neutral light and neutral switch are just two out of several components in the ignition switch circuit – the circuit that leads power from the battery through various components to the electric starter motor.
Here is a diagram showing what a complete ATV ignition switch circuit might look like.
The composition of the component and the wiring layout usually vary slightly from one model to another. Still, the basic principles of how the neutral light operates are the same on most ATVs.
When troubleshooting, you must follow the current path and test the various culprits that could prevent the electricity from flowing as it should.
You might discover variations from the above diagram if you look up your ATV’s wiring diagram.
- Some ATVs have just one neutral switch, while others have several switches next to each other, one for each gear (one neutral switch, one reverse switch, etc.).
- Higher-end modern ATVs typically use a single multipurpose gear selector switch rather than individual switches.
- ATVs with a gear selector switch use a “gear selector resistor module” to relay a different resistance reading to the ECM, depending on the selected gear.
- Older ATVs and some youth models have much simpler wiring where the signal from the neutral switch goes straight to the starter solenoid and not through relays and control units.
Troubleshooting a Neutral Light That Won’t Come On
Like with most other issues you may run into with your ATV, the key to effective and successful troubleshooting is to begin by taking note of the bike’s behavior.
Understanding how the system operates, along with recognizing the symptoms, makes it easier to identify and solve problems through a process of elimination.
Below are the most typical symptoms when the neutral light won’t come on. Begin by taking note of which fits best with your bike’s behavior.
No Neutral Light, No Crank, and No Other Signs of Power
In this scenario, you turn the ignition on and put the bike in neutral, but the neutral light won’t turn on. When you press the starter button, the engine shows no sign of wanting to turn. The dash is dead, and there are no other working lights or signs of the bike getting power.
When this happens, the problem is usually not with the neutral light or safety switch but rather a general power supply issue.
No Neutral Light and No Crank, but the Dash and Headlights Work
In this scenario, you know the bike has power, so there is no point in spending time on battery, fuses, and ignition switches.
The neutral light not turning on and the engine not cranking tells you either the transmission isn’t in neutral or the ATV doesn’t read that it’s in neutral. The ATV falsely thinks it’s in gear and won’t activate the starter.
When this happens, it’s usually an issue with the neutral switch, wiring, connectors, or, worst case, a mechanical transmission issue.
Intermittent No Neutral Light
In this scenario, the neutral light comes and goes. Those times the light is there, the ATV starts as usual. And when it doesn’t turn on, neither will the engine.
This is usually the most time-consuming and possibly frustrating scenario to troubleshoot. The problem is likely damaged wiring or a partially loose connector that connects sometimes and not other times.
There is no Neutral Light, but the ATV Starts as Normal
This is probably the least likely scenario, but it can happen, depending on how your ATV is wired. The fact that the bike starts tells you the neutral safety switch works as usual. The most likely cause in this situation is simply a faulty neutral light bulb.
Causes When the ATV Neutral Light Won’t Come On
Continue your troubleshooting by checking out the possible causes that best fit your ATV’s symptoms and behavior.
1. The ATV Has No Power
When the ATV has no power, the neutral light and all other lights will not turn on. Common causes to look into include:
- A dead battery. Use a multimeter and test the voltage to ensure the battery isn’t dead or drained overnight. Here is how you charge a dead battery.
- A blown main fuse. Check all the fuses in the fuse box. Then, look for the main fuse(s), usually located separately from the fuse panel. On some ATVs, the main fuses can be hidden, like behind the fuse box on some Hondas. Trace the biggest red cable from the battery-positive terminal to locate the fuse(s).
- Loose or corroded ground wires.
- Positive cable short to ground.
- Faulty or corroded ignition switch or kill switch.
Here is a more extensive guide to troubleshooting an ATV that is not getting any power.
2. Unplugged Wire Connector
An unplugged wire connector anywhere in the neutral light/neutral switch circuit will prevent the neutral light from turning green. The wire connector down by the neutral switch is particularly exposed and may have popped off from riding through some brush.
Another common error is forgetting to re-connect one or more connectors or accidentally pulling a wire loose when working on the ATV.
3. Broken Wiring
When the wire insulation on a positive wire is damaged from wear or an impact, you may get a short to ground. When this happens, the neutral light shorts out and stays on regardless of the gear.
But if the wire conductor (the copper metal core) breaks, the current cannot flow down to the neutral switch and, therefore, does not reach ground. A break in the wire will prevent the neutral light from coming on.
To test if a wire conducts (connection is not broken), you can disconnect both ends and test for continuity using a multimeter. Begin with the wire from the neutral light to the neutral switch.
- The black lead goes in the “COM” port (ground).
- The red lead goes in the port labeled “mAVΩ” or “AVΩ.”
- Set the multimeter to continuity, typically indicated by a diode symbol (triangle with a line on the right side) or a sound wave symbol.
- Attach one lead at each end of the wire you’re testing; it doesn’t matter which lead goes where.
- If the multimeter sounds an audible beep or buzzer, there is continuity, and the wire is likely not broken.
If your ATV has a multi-function instrument panel and a gear shift sensor, you will probably need to test several wires.
Identify the corresponding color code wire down by the neutral switch and up by the instrument panel and probe test each wire for proper continuity.
As a final option, if all else fails, is the classic “wiggle test.” Work through the relevant wiring harness and pay attention to the neutral light. If it begins to blink intermittently, you know you are closing in on the problem.
A quick tip to determine if it’s a wiring/connector issue or a bad safety switch is to swap the reverse and neutral light wires down by the transmission. If the reverse light comes on when in neutral, the issue is likely with the wiring.
4. A Faulty or Stuck Neutral Safety Switch
A neutral switch is a mechanical unit that may wear out over time. When the switch doesn’t work, the ATV may think it’s in gear when it’s not.
If the switch displays strange behavior like sticking in one position, it’s an indicator of wear, and it’s likely not long before it stops working altogether.
A switch that sticks may come loose with a light tap of a screwdriver handle. While this may get you out of a pinch, it is not a long-term solution, and the switch will likely get stuck again.
You can test if the switch is working using a multimeter set to continuity. Some ATVs have several switches (one for neutral, one for reverse, one for forward, etc.
Ensure you’re testing the correct switch by removing the connector terminal from the switch assembly and shorting it to ground (frame or engine body). Shorting the connector to ground should cause the corresponding light to light up. Disconnecting the jumper cable will turn the light off.
To test the switch for continuity, put one lead to the switch connector and one to ground. There should be a good continuity reading when the shifter is in neutral. In all other gears, there should not be continuity.
If there is no continuity to ground in neutral or if you read continuity in gears other than neutral, the switch is not working. The most likely cause is a bad switch or possibly an internal transmission issue.
The only permanent solution to a faulty neutral switch safety switch is to replace it.
ATV Neutral Safety Switch Location
The neutral safety switch or gear selector switch is usually on the ATV transmission. Sometimes, the switch is hidden behind the stator cover or by the footpeg behind the sprocket cover.
The design of the switch varies. On some ATVs, it is round, one to two inches in diameter, with two bolts holding it in place. On others, it’s in the shape of a lighter with wires coming out of it.
5. A Faulty Gear Selector Switch
If your ATV has a gear selector rather than a conventional neutral switch, you can also test those for continuity, but the procedure is slightly different.
To test the switch, disconnect the wiring harness connector from it. Then, check the continuity between different switch pins, which will vary depending on the gear the ATV is in.
One pin is always ground, while the others depend on what gear you are testing. You likely need a service manual to identify the proper testing order for your ATV.
The switch needs replacing if there is no continuity or the resistance is too high in any gear position. Please refer to a service manual for specific testing instructions on your ATV.
Check out eManual Online to get factory workshop service and repair manuals for your ATV.
6. Transmission Stuck in Gear
ATV transmissions are complex units with gears that engage and disengage depending on which gear you select.
Sometimes, a transmission may become stuck in one gear so that you can’t get it out of gear and in neutral.
Try rocking the ATV back and forth while operating the shifter in and out of neutral, or keep consistent light pressure on the shifter if it won’t move into neutral. Do not use excessive force, as this may damage the transmission internals further.
If you’re lucky, the shifter eventually slips into neutral, and you may never experience this issue again.
If the problem reoccurs or if you can’t get the shifter to move, you may need a complete transmission rebuild.
7. Loose Transmission Shift Drum
The shaft that operates the neutral switch connects to a switch drum inside the transmission. The drum may no longer activate the switch if it comes loose or out of alignment.
Fixing this issue requires a transmission rebuild.
8. Faulty Gear Selector Resistor Module
When this module fails, the ECM cannot tell which gear the transmission is in.
You need a service manual with a wiring diagram to test the module.
The procedure involves disconnecting the ECM harness connector and testing the wire from the resistor module for resistance.
The reading throughout the various gears should correspond with the values specified in the service manual. If you get a reading, the module needs replacing.
9. Broken Neutral Light Bulb
While not very common, like any light bulb, the neutral light bulb may go out. Replacing the bulb with a new one is relatively cheap, fast, and worth trying if everything else seems fine.
Less Common Reasons for the Neutral Light Not Turning On
Unless your ATV is wired differently than most, here are a couple of causes that are likely not the cause when the light won’t come on.
A Faulty Relay
A relay is like a switch that turns on when all conditions are met. They are cheap and straightforward to replace.
If your ATV is wired so that the signal from the neutral goes through a relay before reaching the neutral light or ECM, it may prevent the neutral light from turning green.
If you suspect a faulty relay causes the issue, you can test it for continuity or listen if it activates. It should make a “click” sound when it turns on.
Faulty Silicon Rectifier Diode (Start Diode)
A diode is like a one-way valve that only allows current to flow in one direction. It is sometimes used in the ignition circuit to prevent the neutral light from turning green as you press the clutch lever or prevent flyback voltage from the starter from damaging the ECU.
On most ATVs with a diode, the diode does not affect whether the neutral light turns green. But if you have access to a wiring diagram, you may follow the path to see if a faulty diode would prevent the neutral light from grounding out.
To test a diode, use a multimeter and test for continuity between the two diode connectors. The red lead goes to the positive side of the diode, and the back lead goes to the opposing side.
When testing in this direction, you should get a continuity reading typically between 0.2 and 0.7. If you switch the multimeter leads and test in the opposite direction, you shouldn’t get any reading.
