Cooling System Switches, Sensors & Relays

The way many systems operate in your vehicle is dependent on the engine coolant temperature, making cooling system switches and sensors very important parts. These components provide an input to the engine control module (ECM), which in turn regulates fuel, ignition and other vehicle functions based on temperature and the input from other sensors. Coolant sensors and switches are threaded into coolant passages, where they are directly exposed to coolant for the most accurate temperature measurement in order to provide the engine control module with real time data.

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    • (0 reviews)
      # sp5723
      Coolant Temperature Sensor by Bosch®. Bosch liquid temperature sensors accurately monitor the vital fluids in your vehicle ensuring long and healthy life. The sensor provides information to the Engine control Unit to keep your engine...
      Extreme Temperature range: -40°F to +260°FRobust Design with High Resistance to Engine Vibrations
      $6.34 - $41.18
    • (0 reviews)
      # sp95475
      Radiator Fan Controller Relay by Four Seasons®. All products are engineered and tested to provide years of trouble free operation. Backed by over 50 years of car parts experience, fix it once and fix it right with Four Seasons.
      OE quality parts from top original equipment and aftermarket manufacturersThe finest quality at a great price
      $27.58 - $121.51
    • (0 reviews)
      # sp9553
      Engine Cooling Fan Module by Beck Arnley®. For one hundred years, Beck Arnley has been providing premium OE quality parts for vehicles. Beginning with motorcycle parts in 1914 and transitioning to import vehicles in the 1950’s, brand...
      OE quality products from top original equipmentTop quality materials
      $31.79 - $227.84
    • (0 reviews)
      # sp114912
      Professional™ Engine Cooling Fan Switch by ACDelco®. Keep your engine cool while utilizing your Air Conditioning System with an ACDelco Engine Cooling Motor. Designed utilizing the latest technology, this product by ACDelco features...
      Conventional and low profile.Space- and weight-efficient.
      +1
      $9.09 - $58.45
    • (0 reviews)
      # sp114805
      Radiator Fan Module by Dorman®. Dorman offers a comprehensive line of Radiator Fan Modules for a range of applications. All the Radiator Fan Modules are constructed from high-quality materials for long-lasting durability.
      Easy to installDirect replacement for a proper fit
      $57.14 - $201.36
    • (0 reviews)
      # sp19598
      Engine Coolant Temperature Sensor by Calorstat®. Increase the life of your vehicle's engine by keeping your cooling system in top condition. Replace your faulty engine cooling component with this highly efficient replacement product and...
      Made to keep your vehicle's engine running coolDesigned to maintain proper cooling level and prevent overheating
      $3.66 - $19.68
    • (0 reviews)
      # sp134213
      Auxiliary Fan Switch by FAE®. Increase the life of your vehicle's engine by keeping your cooling system in top condition. Replace your faulty engine cooling component with this highly efficient replacement product and be sure the heart...
      Made to keep your vehicle's engine running coolDesigned to maintain proper cooling level and prevent overheating
      $5.83 - $46.61
    • (0 reviews)
      # sp132281
      Coolant Temperature Sensor by FAE®. This top-grade product is expertly made in compliance with stringent industry standards to offer a fusion of a well-balanced design and high level of craftsmanship. Manufactured from industry-leading...
      Made to keep your vehicle's engine running coolDesigned to maintain proper cooling level and prevent overheating
      $5.31 - $17.06
    • (0 reviews)
      # sp132283
      Temperature Switch by FAE®. This switch is mounted in the cooling circuit, usually at or near the radiator, and operates with the temperature variation. There are two types of switch: 1) Alarm Thermocontacts 2) Fan Thermocontacts....
      Expertly crafted from the highest grade materialsWill deliver years of reliable service
      $5.55 - $9.69
    • (0 reviews)
      # sp114778
      Engine Coolant Temperature Sensor by Mopar®. Extend the service life of your engine and make it running smoothly with this high-quality product by Mopar. This part was specially designed to maintain the efficiency and performance of...
      Carefully crafted from premium materialsExcellent corrosion and wear resistance
      $31.79
    • (0 reviews)
      # mpn4495939311
      Engine Cooling Fan Motor Relay by Original Engine Management®. OEM offers the highest quality parts available. With vehicle systems becoming more and more complex, electronic components and sensors must be manufactured to precise...
      Made to deliver trouble-free operation for years aheadManufactured with cutting-edge technology
      $6.64
    • (0 reviews)
      # sp127304
      Radiator Fan Switch by Original Engine Management®. Original Engine Management has the most complete line of High Quality and Value radiator fan switches. Unlike a number of other manufacturers who over-consolidate this critical...
      Made to deliver trouble-free operation for years aheadManufactured with cutting-edge technology
      $15.01 - $24.82
    • (0 reviews)
      # mpn259970710
      Auxiliary Fan Control Module by URO Parts®. To keep your vehicle operating at its max, replace your cracked or worn out HVAC part with this superior URO component to optimize your HVAC system and stay cool or warm during your road...
      Designed to replace the original part in your HVAC systemHelps to optimize HVAC system to its proper performance
      $1.82
    • (0 reviews)
      # mpn924410
      Auxiliary Fan Control Module by URO Parts®. Location: Fan. To keep your vehicle operating at its max, replace your cracked or worn out HVAC part with this superior URO component to optimize your HVAC system and stay cool or warm during...
      Designed to replace the original part in your HVAC systemHelps to optimize HVAC system to its proper performance
      $83.95
    • (0 reviews)
      # sp19599
      Engine Cooling Fan Switch by Calorstat®. Increase the life of your vehicle's engine by keeping your cooling system in top condition. Replace your faulty engine cooling component with this highly efficient replacement product and be sure...
      Made to keep your vehicle's engine running coolDesigned to maintain proper cooling level and prevent overheating
      $34.30
    • (0 reviews)
      # mpn4371646243
      Relay by Santech®. Increase the life of your vehicle's engine by keeping your cooling system in top condition. Replace your faulty engine cooling component with this highly efficient replacement product and be sure the heart of your...
      Made to keep your vehicle's engine running coolDesigned to maintain proper cooling level and prevent overheating
      $7.58
    • (0 reviews)
      # mpn4371646243
      Relay by Santech®. 5-Pin. Increase the life of your vehicle's engine by keeping your cooling system in top condition. Replace your faulty engine cooling component with this highly efficient replacement product and be sure the heart of...
      Made to keep your vehicle's engine running coolDesigned to maintain proper cooling level and prevent overheating
      $7.58
    • (0 reviews)
      # mpn4371646243
      Relay by Santech®. Increase the life of your vehicle's engine by keeping your cooling system in top condition. Replace your faulty engine cooling component with this highly efficient replacement product and be sure the heart of your...
      Made to keep your vehicle's engine running coolDesigned to maintain proper cooling level and prevent overheating
      $7.58
    • (0 reviews)
      # mpn4371646243
      Relay by Santech®. Increase the life of your vehicle's engine by keeping your cooling system in top condition. Replace your faulty engine cooling component with this highly efficient replacement product and be sure the heart of your...
      Made to keep your vehicle's engine running coolDesigned to maintain proper cooling level and prevent overheating
      $7.58
    • (0 reviews)
      # mpn4371646243
      Relay by Santech®. Increase the life of your vehicle's engine by keeping your cooling system in top condition. Replace your faulty engine cooling component with this highly efficient replacement product and be sure the heart of your...
      Made to keep your vehicle's engine running coolDesigned to maintain proper cooling level and prevent overheating
      $7.58
    • (2 reviews)
      # mpn4476156895
      Relay by Santech®. 4-Pin with Blue Housing. This application uses a 4-pin relay with a blue plastic housing in either Niles brand (#25230-C9970) or Miyamoto brand (#25230-C9980). Either of the two brands is interchangeable and is...
      Made to keep your vehicle's engine running coolDesigned to maintain proper cooling level and prevent overheating
      $31.69
    • (0 reviews)
      # mpn4371646243
      Relay by Santech®. 5-Pin. Increase the life of your vehicle's engine by keeping your cooling system in top condition. Replace your faulty engine cooling component with this highly efficient replacement product and be sure the heart of...
      Made to keep your vehicle's engine running coolDesigned to maintain proper cooling level and prevent overheating
      $7.58
    • (0 reviews)
      # mpn4371646243
      Relay by Santech®. Increase the life of your vehicle's engine by keeping your cooling system in top condition. Replace your faulty engine cooling component with this highly efficient replacement product and be sure the heart of your...
      Made to keep your vehicle's engine running coolDesigned to maintain proper cooling level and prevent overheating
      $7.58
    • (0 reviews)
      # mpn4371646243
      Relay by Santech®. Increase the life of your vehicle's engine by keeping your cooling system in top condition. Replace your faulty engine cooling component with this highly efficient replacement product and be sure the heart of your...
      Made to keep your vehicle's engine running coolDesigned to maintain proper cooling level and prevent overheating
      $7.58
    • (2 reviews)
      # mpn4476156895
      Relay by Santech®. With 4 Pin Connector. With Blue Housing. Increase the life of your vehicle's engine by keeping your cooling system in top condition. Replace your faulty engine cooling component with this highly efficient replacement...
      Made to keep your vehicle's engine running coolDesigned to maintain proper cooling level and prevent overheating
      $31.69
    • (0 reviews)
      # mpn4371646243
      Relay by Santech®. Increase the life of your vehicle's engine by keeping your cooling system in top condition. Replace your faulty engine cooling component with this highly efficient replacement product and be sure the heart of your...
      Made to keep your vehicle's engine running coolDesigned to maintain proper cooling level and prevent overheating
      $7.58
    • (0 reviews)
      # mpn4371646243
      Relay by Santech®. 5-Pin. Increase the life of your vehicle's engine by keeping your cooling system in top condition. Replace your faulty engine cooling component with this highly efficient replacement product and be sure the heart of...
      Made to keep your vehicle's engine running coolDesigned to maintain proper cooling level and prevent overheating
      $7.58
    • (0 reviews)
      # mpn4371646243
      Relay by Santech®. 5-Pin. Increase the life of your vehicle's engine by keeping your cooling system in top condition. Replace your faulty engine cooling component with this highly efficient replacement product and be sure the heart of...
      Made to keep your vehicle's engine running coolDesigned to maintain proper cooling level and prevent overheating
      $7.58
    • (0 reviews)
      # mpn4371646243
      Relay by Santech®. 5-Pin. Increase the life of your vehicle's engine by keeping your cooling system in top condition. Replace your faulty engine cooling component with this highly efficient replacement product and be sure the heart of...
      Made to keep your vehicle's engine running coolDesigned to maintain proper cooling level and prevent overheating
      $7.58
    • (0 reviews)
      # mpn4371646243
      Relay by Santech®. 5-Pin. Increase the life of your vehicle's engine by keeping your cooling system in top condition. Replace your faulty engine cooling component with this highly efficient replacement product and be sure the heart of...
      Made to keep your vehicle's engine running coolDesigned to maintain proper cooling level and prevent overheating
      $7.58




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    Coolant switches are used when a simple on/off signal is needed, as in the early fuel evaporation (EFE) system, which is used on some carbureted vehicles to heat the fuel mixture when the engine is cold to improve vaporization. In this system, a plate, with a heater grid under one or both carburetor barrels, is installed between the carburetor and the intake manifold. A temperature switch grounds the EFE circuit when the vehicle is cold and a relay supplies power to the heater grid. When the engine reaches a specified operating temperature, the switch opens, deactivating the relay and shutting off the heater grid.

    When a range of coolant temperature data is required, a coolant temperature sensor is needed. A common use for these data would be for a temperature gauge. Most coolant temperature sensors are thermistors, which change resistance according to temperature. Most of these are NTC (negative temperature coefficient) thermistors, which decrease resistance as temperature increases. The ECM sends a 5-volt reference voltage to the sensor and the sensor’s resistance reduces the voltage sent back to the computer. The temperature is calculated by the ECM based on the return voltage.

    The ECM uses temperature data from the coolant temperature sensor to: vary injector pulse width, increasing on-time for a richer mixture when the engine is cold, and decreasing on-time as the engine warms up; increase idle speed when the engine is cold, to prevent stalling; and turn the electric cooling fan on and off. In addition, coolant temperature information is critical because certain component function must only be enabled when the engine is warm. These include the EGR (exhaust gas recirculation) system, which would cause the engine to run rough and stall if exhaust gas was introduced to the intake when the engine is cold; the evaporative emissions control purge valve; and the transmission torque converter clutch.

    Some of the engine cooling system components, for example, a radiator fan, draw a high current from the power source. If you connect them directly or using a switch to the alternator or the battery, it may cause a short circuit, which can result in a fire or damage to the battery. To avoid such a turn of events, virtually all electric engine cooling system components are connected to the circuit through a relay. It is a small electromagnetic switch operated by a relatively small electric current that can turn on or off a much larger electric current. This allows to power any energy-intensive devices without running the risk of damaging the battery or other vehicle components. Relays vary in size and construction, while their operating principle remains the same.

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    Cooling System Switches, Sensors & Relays Reviews

    Average rating:  5  5 - 17 reviews
    5 of 5
    Works as Intended
    Half the price as the parts store.
    RPosted by Raymond Gaudreau (Fremont, NE) / May 17, 20182000 Chevy Venture
    Was this review helpful for you? Yes
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