1. Introduction
This manual provides essential information for the proper installation, operation, and maintenance of the Valeo Service 819744 Thermo Switch. Please read these instructions carefully before proceeding with installation or use to ensure optimal performance and safety. This thermo switch is designed for specific automotive applications to monitor and regulate engine temperature.
2. Product Overview
The Valeo Service 819744 Thermo Switch is an automotive component designed to activate or deactivate a circuit based on a specific temperature threshold. It functions as a critical part of the engine cooling system, typically controlling the radiator fan or other temperature-dependent systems. This model features a normally open contact type and operates in an ON-OFF mode.
Figure 1: Front view of the Valeo Service 819744 Thermo Switch. This image shows the brass threaded body, the metal washer, and the black plastic housing with two electrical terminals at the top.
Key features of the Valeo Service 819744 Thermo Switch include:
- Closing temperature: 82°C
- Opening temperature: 92°C
- Spanner Size: 29 mm
- Weight: 0.059 kg
This part is compatible with various vehicle models, including but not limited to:
- Renault Super 5 Hatchback 1.4 Turbo (1984 - 1996)
- Renault Trafic Van 1.6, 1.7, 2.0 (1980 - 1989)
- Renault Master I Van 2.4 D (1980 - 1998)
- Renault 5 Hatchback 1.4 Turbo, 1.1 (1972 - 1985)
- Renault 4 Box 1.1 (1966 - 1993)
- Alfa Romeo 145 Hatchback 1.4 i.e. (1994 - 2001)
Figure 2: Angled view of the Valeo Service 819744 Thermo Switch, highlighting the threaded connection and electrical terminals.
3. Installation
Installation of the Valeo Service 819744 Thermo Switch should ideally be performed by a qualified automotive technician. Incorrect installation can lead to system malfunction, engine damage, or personal injury.
3.1 Safety Precautions
- Always disconnect the vehicle's battery before beginning any electrical work.
- Allow the engine to cool completely before working on the cooling system to avoid burns from hot coolant or engine components.
- Wear appropriate personal protective equipment, including gloves and eye protection.
- Ensure the vehicle is securely supported if lifted.
3.2 Installation Steps
- Locate the existing thermo switch or the designated mounting point for the new switch in your vehicle's cooling system (e.g., radiator, engine block, thermostat housing).
- Drain a sufficient amount of coolant from the system to prevent spillage when removing the old switch.
- Carefully remove the old thermo switch using a 29 mm spanner or appropriate tool. Be prepared for some coolant leakage.
- Clean the mounting area thoroughly to ensure a proper seal.
- Apply a small amount of thread sealant (if recommended by vehicle manufacturer) to the threads of the new Valeo 819744 Thermo Switch.
- Thread the new switch into place by hand to prevent cross-threading.
- Tighten the switch to the manufacturer's specified torque using a 29 mm spanner. Do not overtighten.
- Connect the electrical wiring to the terminals of the new switch. Ensure connections are secure and free from corrosion.
- Refill the cooling system with the correct type and amount of coolant, bleeding any air from the system as per vehicle manufacturer guidelines.
- Reconnect the vehicle's battery.
- Start the engine and check for leaks and proper operation of the cooling fan or related components. Monitor engine temperature closely.
4. Operation
The Valeo Service 819744 Thermo Switch operates automatically based on the temperature of the coolant it is immersed in. As a normally open switch, its contacts remain open (circuit off) until the coolant reaches its specified closing temperature of 82°C. At this point, the switch closes, completing the circuit and typically activating the radiator fan or another cooling system component.
When the coolant temperature drops to the opening temperature of 92°C (or below, depending on hysteresis), the switch contacts will open again, deactivating the circuit. This ON-OFF operation ensures that the engine's temperature is maintained within optimal operating parameters, preventing overheating.
5. Maintenance
The Valeo Service 819744 Thermo Switch is designed for durability and typically requires minimal maintenance. However, regular inspection of the cooling system can help ensure its longevity and proper function.
- Visual Inspection: Periodically check the switch and its wiring for any signs of damage, corrosion, or loose connections.
- Coolant Quality: Ensure the vehicle's coolant is maintained at the correct level and quality. Contaminated or low coolant can affect the switch's ability to accurately sense temperature.
- System Leaks: Regularly inspect the entire cooling system for leaks, which can lead to air pockets and improper temperature readings.
If any issues are observed, consult a qualified technician for diagnosis and repair.
6. Troubleshooting
If you suspect a problem with your Valeo Service 819744 Thermo Switch or the cooling system, consider the following common issues and diagnostic steps:
- Radiator Fan Not Activating:
- Check the electrical connections to the thermo switch and the fan motor.
- Verify the fan motor itself is functional (e.g., by direct power).
- Test the thermo switch's continuity at specified temperatures (requires specialized equipment or professional assistance).
- Ensure the engine is reaching the closing temperature (82°C) for the fan to activate.
- Radiator Fan Running Constantly:
- The thermo switch may be stuck in the closed position.
- Check for short circuits in the wiring.
- Verify the engine temperature is dropping below the opening temperature (92°C).
- Engine Overheating:
- This could indicate a faulty thermo switch, but also other cooling system issues (low coolant, faulty thermostat, clogged radiator, water pump failure).
- Do not rely solely on the thermo switch as the cause; a comprehensive cooling system diagnosis is recommended.
For complex issues or if you are unsure about diagnostic procedures, it is highly recommended to consult a certified automotive mechanic.
7. Specifications
Figure 3: Valeo Service 819744 Thermo Switch with approximate dimensions shown (3.0 inches / 7 cm).
| Specification | Value |
|---|---|
| Model Number | 819744 |
| Brand | Valeo |
| Closing Temperature | 82°C |
| Opening Temperature | 92°C |
| Spanner Size | 29 mm |
| Weight | 0.059 kg (1.41 ounces) |
| Product Dimensions (L x W x H) | 9.12 x 5.57 x 3.4 inches |
| Operation Mode | ON-OFF |
| Contact Type | Normally Open |
| Connector Type | Plug In |
| Terminal Type | Screw |
| Circuit Type | 1-way |
| Actuator Type | Push Button |
| Contact Material | Metal |
| International Protection Rating | IP00 |
| First Available Date | July 23, 2014 |
8. Warranty and Support
Specific warranty information for the Valeo Service 819744 Thermo Switch is typically provided at the point of purchase or through the official Valeo website. Please retain your proof of purchase for warranty claims.
For technical support, product inquiries, or warranty service, please contact Valeo customer service or visit their official website. You can find more information about Valeo products and support at the Valeo Store.
