Bypassing The Clutch Interlock Switch For Remote Start Or Aftermarket Ecus

The clutch interlock switch is a safety feature found in most manual transmission vehicles. Its primary function is to prevent the engine from starting unless the clutch pedal is fully depressed. This prevents the car from lurching forward unexpectedly, potentially causing accidents. However, some situations, such as installing a remote start system or an aftermarket ECU, may require bypassing the clutch interlock switch. Before considering this modification, it’s crucial to understand the implications and potential risks involved.

Understanding the Clutch Interlock Switch

The clutch interlock switch is a simple yet effective device. It’s typically a small electrical switch located near the clutch pedal assembly. When the clutch pedal is pressed, the switch closes, completing the circuit and allowing the starter motor to engage. When the pedal is released, the switch opens, breaking the circuit and preventing the engine from starting. This mechanism ensures that the driver intends to start the car and has control over the drivetrain.

Why Bypass the Clutch Interlock Switch?

While the clutch interlock switch is a valuable safety feature, there are a few reasons why someone might consider bypassing it:

• Remote Start Systems: Most remote start systems are designed to work with automatic transmissions. When installing a remote start in a manual vehicle, the system needs a way to start the engine without physically depressing the clutch. Bypassing the interlock switch is often necessary to achieve this.
• Aftermarket ECUs: Certain aftermarket engine control units (ECUs) may require bypassing the interlock switch for proper functionality. This is particularly true if the ECU is designed for racing or performance applications where quick starts are essential.
• Troubleshooting Starting Issues: In some cases, a faulty clutch interlock switch can prevent the car from starting. Bypassing the switch can be a temporary diagnostic step to determine if the switch is the source of the problem. However, this should not be considered a permanent solution.

Methods for Bypassing the Clutch Interlock Switch

There are several methods for bypassing the clutch interlock switch, each with its own level of complexity and risk. It's important to choose a method that you're comfortable with and to exercise caution throughout the process.

Method 1: The Jumper Wire

This is the simplest, but also potentially the most dangerous, method. It involves directly connecting the two wires that lead to the clutch interlock switch, effectively creating a permanent closed circuit. This means the car will start regardless of the clutch pedal position.

1. Locate the Clutch Interlock Switch: Find the switch near the clutch pedal. It's usually a small plastic component with two wires connected to it.
2. Disconnect the Wires: Carefully disconnect the wires from the switch. Make sure the ignition is off.
3. Connect the Wires: Use a short length of wire (a "jumper wire") to connect the two disconnected wires together. Ensure the connection is secure and insulated.
4. Test the System: Turn the ignition on and try to start the car without pressing the clutch pedal. If the car starts, the bypass is successful.

Important Considerations:

This method completely disables the safety feature of the clutch interlock switch. The car can now start in gear, potentially causing serious accidents. Proceed with extreme caution. This method is generally not recommended for long-term use.

Method 2: Using a Relay

This method is considered safer than the jumper wire method because it allows you to control the bypass circuit. A relay acts as an intermediary switch, allowing you to temporarily bypass the interlock switch when needed, such as when using a remote starter.

1. Locate the Clutch Interlock Switch: As with the previous method, find the switch near the clutch pedal.
2. Identify the Wires: Determine which wire carries the signal when the clutch pedal is pressed (use a multimeter if necessary).
3. Wire the Relay: Connect the relay according to its specific wiring diagram. Typically, you'll need to connect the relay's coil to a 12V power source and ground, and the relay's contacts in series with the clutch interlock switch circuit. This means cutting one of the wires going to the interlock switch and connecting the two cut ends to the relay's normally open (NO) contacts.
4. Control the Relay: The relay can be activated by a remote start system or a separate switch. When the relay is activated, it closes the circuit, bypassing the interlock switch.
5. Test the System: Test the relay to ensure it bypasses the switch only when activated.

Important Considerations:

This method requires a basic understanding of electrical wiring and relays. A wiring diagram is essential for proper installation. Ensure the relay is properly rated for the voltage and current of the circuit.

Method 3: Using a Clutch Position Sensor (CPS) Simulator

This method is often used in conjunction with aftermarket ECUs. A CPS simulator mimics the signal that the ECU expects to see from the clutch position sensor when the clutch pedal is depressed. This allows the ECU to function correctly without the need for the actual clutch interlock switch.

1. Consult the ECU Documentation: The specific wiring and configuration for a CPS simulator will vary depending on the ECU and the simulator being used. Consult the ECU's documentation for detailed instructions.
2. Install the CPS Simulator: Follow the instructions provided with the simulator to wire it into the vehicle's electrical system and connect it to the ECU.
3. Configure the ECU: Configure the ECU to recognize the signal from the CPS simulator. This may involve adjusting parameters such as the clutch position threshold.
4. Test the System: Test the system to ensure the ECU functions correctly and the engine starts without the need to depress the clutch pedal.

Important Considerations:

This method is the most complex and requires a thorough understanding of the ECU and the CPS simulator. Improper installation or configuration can damage the ECU or other vehicle components. It's often best to consult with a professional tuner or installer.

Safety Precautions and Legal Considerations

Bypassing the clutch interlock switch is a modification that should be approached with caution. Here are some important safety precautions and legal considerations:

• Safety First: Always prioritize safety. Ensure the vehicle is parked on a level surface with the parking brake engaged before working on the electrical system. Disconnect the battery's negative terminal to prevent accidental shorts.
• Thorough Testing: After bypassing the switch, thoroughly test the system to ensure it functions as intended. Pay close attention to the starting behavior of the car in various scenarios.
• Warning Labels: If you bypass the clutch interlock switch, consider placing a warning label in the vehicle to alert other drivers to the modification.
• Legal Compliance: Check your local laws and regulations regarding modifications to vehicle safety systems. Bypassing the clutch interlock switch may be illegal in some jurisdictions.
• Insurance Implications: Modifying safety systems can potentially affect your insurance coverage. Consult with your insurance provider to understand the implications.
• Professional Installation: If you're not comfortable performing the bypass yourself, seek professional help from a qualified mechanic or automotive electrician.

Alternatives to Bypassing

Before resorting to bypassing the clutch interlock switch, consider whether there are alternative solutions. For example, some remote start systems are specifically designed to work with manual transmissions and include features that ensure safe operation. These systems typically use a more sophisticated approach, such as requiring the driver to engage the parking brake and confirm the car is in neutral before the remote start system will activate. Also, addressing a faulty switch directly through replacement is always the safest approach.

Conclusion

Bypassing the clutch interlock switch is a modification that can be necessary in certain situations, such as installing a remote start system or an aftermarket ECU. However, it's crucial to understand the implications, potential risks, and legal considerations involved. If you choose to bypass the switch, do so with caution and prioritize safety. Consider consulting with a professional if you're not comfortable performing the modification yourself. Remember that the clutch interlock switch is a vital safety feature, and disabling it can increase the risk of accidents. Always explore alternative solutions before resorting to a bypass.