HOME >> NEWS >> How to Connect PTC Heater?

How to Connect PTC Heater?

Connecting a PTC (Positive Temperature Coefficient) heater in an electric or hybrid vehicle requires precision, safety awareness, and a deep understanding of high-voltage systems. Because a PTC heater operates at voltages between 300V–800V, correct wiring is crucial for both performance and safety.

In this guide, we’ll explain step-by-step how to properly connect a PTC heater using professional-grade components such as the Custom PTC Heater High-Voltage New Energy Vehicle Wiring Harness, EV PTC heater power harness, and High-Voltage Interlock Loop (HVIL) harness.

Understanding the PTC Heater Circuit

Before starting the installation, it’s essential to understand how a PTC heater fits into the vehicle’s electrical system. The heater typically connects to: the traction battery pack (high-voltage source), the Body Control Module (BCM) or HVAC control unit (signal input), and the grounding system for electrical stability. Power and signal are transmitted through a high-voltage PTC heater wiring harness, designed to resist high current, temperature, and electromagnetic interference.

Required Components and Tools

To complete a proper connection, you’ll need the following:

Custom PTC Heater High-Voltage New Energy Vehicle Wiring Harness
HV orange shielded cable assembly
High-Voltage Interlock Loop (HVIL) harness
Connector locking clips
Torque wrench, crimping tool, and insulation tape
Multimeter for verification

Each cable in the HV orange shielded cable assembly is shielded to reduce signal noise and ensure safety during operation.

Step-by-Step Connection Process

Step 1: Disconnect the Power Source
Always start by disconnecting the vehicle’s high-voltage battery. Safety first — make sure the HVIL circuit is open before handling any connectors.

Step 2: Mount the PTC Heater
Position the PTC heater inside the HVAC system or battery thermal management unit. Ensure that the mounting points are vibration-proof and thermally insulated.

Step 3: Connect the Power Lines
Attach the EV PTC heater power harness to the PTC heater terminals. The positive (+) and negative (–) terminals are clearly labeled. Use an HV orange shielded cable assembly to connect the harness to the high-voltage junction box or relay module.

Step 4: Install the HVIL Harness
The high-voltage interlock loop (HVIL) harness should be connected last. This circuit ensures that the power remains disconnected until all connectors are securely locked. If any cable or plug is loose, the HVIL signal interrupts the high-voltage system automatically.

Step 5: Connect the Control Signal Lines
The Custom PTC Heater High-Voltage New Energy Vehicle Wiring Harness includes low-voltage control wires for temperature regulation and CAN communication. Connect these to the BCM or vehicle thermal control ECU.

Step 6: Verify and Test
Once all connections are made, use a multimeter to check insulation resistance and continuity. Reconnect the power source and test the heater for proper function. If the PTC heater activates and self-regulates its temperature, the installation has been successful.

Safety Tips

Always wear high-voltage insulated gloves when working on EV systems.
Use cables rated for >600V continuous load.
Avoid routing cables near heat sources or moving mechanical parts.
Ensure that the HV orange shielded cable assembly remains intact with no visible cracks or abrasions.
Verify the HVIL harness functionality before restoring power.

Following these steps ensures that the heater and its wiring system operate safely and efficiently.

Common Mistakes to Avoid

Mixing up positive and negative terminals.
Failing to lock HV connectors properly.
Using unshielded wires instead of high-voltage PTC heater wiring harnesses.
Ignoring grounding requirements, which may cause electrical interference or malfunction.

The Custom PTC Heater High-Voltage New Energy Vehicle Wiring Harness helps prevent these errors through labeled connectors, waterproof design, and precise pin alignment.

Summary

Properly connecting a PTC heater is critical for the safe and efficient operation of electric vehicles. With the right components — including the EV PTC heater power harness, HV orange shielded cable assembly, and High-Voltage Interlock Loop (HVIL) harness — the process becomes straightforward and secure. Professional wiring ensures not only heating performance but also long-term system reliability in high-voltage automotive applications.