All vehicles come with fuses that protect the vehicle by preventing overcurrent and isolating the faulty component to prevent it from damaging other parts of the car’s electrical system so that the rest of the car’s electrical functions can operate normally.
The neutral safety switch prevents the engine from starting while the transmission is in gear, ensuring the vehicle can only be started in the “Neutral” or “Park” position when you must have complete control over the car’s movement. But, does the switch have a fuse? Is there a fuse for the neutral safety switch?
No, a neutral safety switch does not have a dedicated fuse, rather, the switch itself functions as a safety mechanism by controlling the electrical circuit that allows the starter to crank the engine. However, some vehicles may have a fuse for the starter motor circuit, which would indirectly affect the neutral safety switch functionality.
Is There a Fuse for the Neutral Safety Switch?
No, in most vehicles, there isn’t a fuse dedicated solely to the neutral safety switch itself, rather, the neutral safety switch is integrated into the vehicle’s electrical system and is often part of the transmission range sensor or inhibitor switch.
Unlike some other electrical components in a vehicle, such as headlights or power windows, the neutral safety switch itself does not usually have its own dedicated fuse.
Instead, the functions associated with the switch are protected by fuses or relays that safeguard various components within the vehicle’s electrical system.
In modern vehicles, the electrical system is divided into multiple circuits, each protected by its own fuse or relay.
These fuses and relays are housed in a fuse box or power distribution center located within the engine bay or interior cabin of the vehicle. They serve to protect sensitive electronic components and prevent electrical overloads that could lead to damage or malfunction.
While there isn’t a specific fuse labeled “Neutral Safety Switch” in the fuse box, several fuses and relays may indirectly affect the operation of the neutral safety switch.
For instance, the starting circuit such as the ignition switch, starter motor, and transmission control module, is usually protected by fuses or relays. If any of these components experience a fault or malfunction, it can indirectly affect the operation of the neutral safety switch.
Therefore, If you’re experiencing issues related to the neutral safety switch, such as difficulty starting the vehicle or problems with the transmission shifting properly, you’re urged to check the fuses and relays in the fuse box to ensure they are not blown or malfunctioning.
The fact that there may not be any fuse dedicated to the switch in your vehicle doesn’t mean you will not check other relevant fuses.
You can start by checking the fuses and relays associated with the starting circuit to help identify and resolve any electrical issues that may be affecting the operation of the neutral safety switch.
Meanwhile, while checking the fuses and relays, it’s also important to consider other factors that could affect the functionality of the switch.
Wiring issues, such as corroded or damaged connections, can disrupt the flow of electricity and prevent the switch from operating correctly.
Furthermore, a damaged or faulty neutral safety switch itself can also cause starting problems or issues with transmission shifting.
How Do You Know When a Neutral Safety Switch Is Bad?
Here are some common signs that can indicate a bad neutral safety switch:
1. The Car Will Start When the Gear is in Drive
One way to know that your neutral safety switch has gone bad is if your car starts when the gear is in the drive.
As reiterated earlier, the purpose of the safety switch is to prevent the car from starting when the car is in drive. Therefore, if your car starts when the gear is in drive, then the safety switch is bad.
This reminds me of a situation that happened the day my friend drove my car. On that faithful day, we had gotten to our location and the young man turned the car off without putting the gear in park. Though we were still inside the car.
Because the person we came looking for was not around, we needed to leave. He tried starting the car and it refused to start. While I was in the passenger seat, I tried helping him press the thumb start, yet the car refused to start.
I noticed that my Lexus IS350 thumb start is red in color instead of green. Normally, the color is supposed to be green to show it detected the key fob. That’s when I noticed that something was wrong.
At first, I thought the key fob battery had gone bad. But then I looked closely and saw that the gear was still in drive. My friend had failed to put the gear in the drive before turning the car off.
So, I asked him to press down the brake pedal, shifted the gear to park, and ask him to start the car again. Immediately, the car started. We looked at ourselves and laughed so hard. It was funny.
My car refused to start while the gear was in drive because the safety switch was still in good condition. However, if the switch has gone bad, it will allow the engine to start when the transmission is in gear, posing a safety risk.
Had it been the car started, a 306 horsepower Lexus IS350, my friend may not have been able to control the car because he’s still learning how to drive.
2. The Car May Refuse to Start
One of the primary functions of the neutral safety switch is to prevent the engine from starting when the transmission is in gear.
If the switch fails or malfunctions, it may prevent the engine from starting altogether, even when the transmission is in the “Park” or “Neutral” position.
3. The Car Will be Starting Intermittently
A faulty neutral safety switch can sometimes cause intermittent starting issues. The engine may start normally on some occasions but fail to start on others. This inconsistency in starting behavior can be frustrating and may indicate a problem with the switch.
4. Transmission Shifting Problems
In some cases, a malfunctioning neutral safety switch can cause issues with the transmission shifting properly. You may experience difficulty shifting gears or notice erratic shifting behavior, such as unexpected gear changes or delays in engagement.
5. Reverse Lights Stay On or Do Not Illuminate
Since the neutral safety switch is also responsible for activating the reverse lights when the transmission is in the “Reverse” position, if the switch fails, it may cause the reverse lights to stay illuminated at all times or fail to come on when the vehicle is shifted into reverse.
6. Check Engine Light
A faulty neutral safety switch can sometimes trigger the vehicle’s onboard diagnostic system to illuminate the check engine light.
The CEL may indicate trouble codes related to transmission range sensor or neutral safety switch failures, providing additional clues for diagnosis.
Therefore, if you experience any of these symptoms, have your car inspected to determine whether the neutral safety switch is indeed the source of the problem or if other issues are contributing to the symptoms.
Even though the safety switch doesn’t spoil that easily, it doesn’t mean it does not spoil at all. Inspecting the switch might tell you what you need to know.
Is There a Way to Test a Neutral Safety Switch?
Yes, there are several methods to test a neutral safety switch to determine if it’s functioning correctly. Here’s a step-by-step guide on how to test a neutral safety switch:
Step 1: Locate the Neutral Safety Switch
The neutral safety switch is usually located on the side of the transmission housing. You can also check your vehicle’s service manual to find its exact location.
Step 2: Inspect the Switch and Wiring
Before testing the switch, it is good to visually inspect the switch and its wiring harness for any signs of damage, corrosion, or loose connections to ensure that the switch is securely mounted and that the wiring is in good condition.
Step 3: Check for Power
The next step at testing the neutral safety switch is checking for power. You can do this by:
- Getting a digital multimeter set to measure DC voltage
- Disconnect the electrical connector from the neutral safety switch
- Turn the ignition key to the “ON” position without starting the engine
- Use the multimeter’s positive lead to probe the wire harness connector terminal that supplies power to the switch, and use the negative lead to ground
- You should see battery voltage usually 12 volts on the meter if power is reaching the switch.
Step 4: Test Continuity in Park and Neutral
With the transmission in the “Park” position, use the multimeter set to measure continuity (ohms) to test for a complete circuit between two specific terminals on the NSS connector.
The exact terminals will vary depending on the vehicle make and model, so check the service manual for the correct terminals.
There should be continuity (a complete electrical path) between the specified terminals when the transmission is in “Park” and “Neutral.”
Step 5: Test Continuity in Other Gears
Repeat the continuity test while shifting the transmission through each gear position. The continuity readings should change accordingly. However, there should be no continuity in any other gear position besides “Park” and “Neutral.”
Step 6: Test Reverse Light Functionality
The neutral safety switch also activates the vehicle’s reverse lights when the transmission is in the “Reverse” position. Therefore, to test this function, reconnect the switch electrical connector and turn the ignition key to the “ON” position.
With the transmission in “Park” or “Neutral,” manually shift it into “Reverse” while observing the reverse lights. They should illuminate when the transmission is in the “Reverse” position.
Step 7: You can Use a Scan Tool to Perform the Test
If your vehicle is equipped with an OBD system, you can also use a scan tool to check for any trouble codes related to the neutral safety switch or transmission range sensor. It can provide additional diagnostic information if available.
By following these steps, you can perform a comprehensive test of the neutral safety switch to determine if it’s functioning properly.
If any issues are detected during the testing process, such as lack of continuity or failure to activate the reverse lights, it may indicate a faulty neutral safety that requires adjustment, repair, or replacement.
What Powers the Neutral Safety Switch?
The neutral safety switch is powered by the vehicle’s ignition switch which supplies electrical power to the switch when the ignition key is turned to the “ON” position.
This power allows the neutral safety switch to perform its function of preventing the engine from starting when the transmission is not in the appropriate gear position.
When you turn the ignition key to the “ON” position, electrical power flows from the battery through the ignition switch to various components in the vehicle, including the neutral safety switch.
Nonetheless, the ignition switch acts as a gateway that allows or interrupts the flow of electrical power to different systems and components depending on the position of the key.
In the case of the neutral safety switch, power is supplied to it when the ignition key is turned to the “ON” position, regardless of whether the engine is started or not.
Conclusion
Depending on your brand, make, and model of your vehicle, there may not be a fuse for the neutral safety switch available. Therefore, if your vehicle is experiencing issues related to starting or problems with the transmission shifting properly, check other fuses and relays in the fuse box to be sure they are in good condition.
