12V DC QOS Thermo Switch with Corrosion-Resistant Housing for ISUZU 4JB1 Direct OEM Replacement

Precision-engineered QOS thermo switch monitors engine temperature and controls the quick-on-start (QOS) glow plug system, ensuring reliable cold-start performance for ISUZU 4JB1 diesel engines.

• OE Quality: Manufactured to strict ISUZU dimensional and temperature specifications for perfect fit and function
• Precision Temperature Sensing: Accurate ON/OFF switching at the correct temperature for proper glow plug operation
• Durable Construction: Corrosion-resistant housing withstands harsh under-hood conditions
• Reliable Cold Starts: Ensures glow plugs activate at the correct temperature for reliable starting in cold weather
• Protects Glow Plugs: Prevents over-heating and premature burn-out of glow plugs
• Protects the Battery: Prevents unnecessary electrical draw that can drain the battery
• Direct Replacement: Simple installation during cold-start system service
• Long Service Life: Engineered to withstand the rigors of heavy-duty commercial operation
• Essential Component: Critical for reliable cold-start performance and engine protection

This QOS thermo switch is specifically designed for ISUZU light-duty trucks. Common applications include:

• ISUZU NKR55 - Light-Duty Trucks
• ISUZU NKR (various models with 4JB1 engine)
• ISUZU NPR (select light-duty models with 4JB1 engine)
• ISUZU ELF (select models)
• ISUZU TF Series (select models)

• 4-Cylinder, Inline Diesel
• Displacement: 2.8L (2771cc)
• Naturally Aspirated or Turbocharged (4JB1T)
• Widely used in NKR55 and various light-duty applications

Professional installation recommended. Proper electrical safety is essential:

1. Disconnect battery - Disconnect the negative battery cable before beginning work
2. Drain coolant partially - Drain enough coolant to a level below the thermo switch mounting point
3. Locate the QOS thermo switch - Identify the thermo switch on the engine (typically near the thermostat housing or cylinder head)
4. Disconnect the electrical connector - Carefully unplug the wiring harness connector from the switch
5. Remove the old switch - Unscrew and remove the old thermo switch
6. Inspect the mounting threads - Check the mounting hole threads for damage or debris
7. Clean the mounting area - Clean the mounting threads and surrounding area
8. Apply thread sealant - Apply a small amount of thread sealant or thread tape if specified
9. Prepare the new switch - Inspect the new switch and verify it matches the original
10. Install the new switch - Thread the new thermo switch into the mounting hole
11. Torque to specification - Tighten to manufacturer specification
12. Reconnect the electrical connector - Plug the wiring harness into the new switch
13. Refill coolant - Refill the cooling system with the correct type and mixture of coolant
14. Reconnect battery - Reconnect the negative battery cable
15. Start the engine - Start the engine and check for leaks around the switch
16. Verify operation - Check that the glow plug system functions correctly when the engine is cold

• Material Verification: Confirms housing and sensing element materials meet OE specifications
• Dimensional Inspection: Housing dimensions, mounting threads, and connector configuration verified against OEM tolerances
• Temperature Calibration: ON/OFF switching temperature verified to OE specifications
• Electrical Testing: Switch continuity and operation verified at specified temperatures
• Sealing Integrity: Switch sealing verified to prevent coolant and moisture ingress
• Visual Inspection: 100% checked for defects, damage, or imperfections
• Packaged Safely: Protected and securely packaged to prevent damage during transit

• Neutral export packing or customized packaging available
• Carton or wooden case for safe transportation
• Fast delivery for stock items
• Shipping by Express Air or Sea