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Flex-a-lite

Flex-A-Lite Variable Speed Controller and Relay Kit with Thread-In Temperature Sensor, Fan Controller With Temperature Probe (31163), Black

  • Based on 142 reviews
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Availability: Only 6 left in stock, order soon!
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Arrives Saturday, Aug 15
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Features

  • One Flex-A-Lite Variable Speed Controller with Electric Fan Relay Kit and Thread-In Temperature Sensor (31163)
  • This variable speed cooling fan controller has a built-in relay function, which means no need for external relays
  • Flex-A-Lite Variable Speed Control Module includes 1/4-inch NPT threaded temperature probe with 3/8-inch and 1/2-inch thread adapters
  • Automotive fan controller starts fans at 60 percent power and increases speed as temperature rises; and runs fans for up to 25 seconds after the vehicle is turned off to remove excess radiator heat
  • The Flex-A-Lite Variable Speed Controller is the perfect companion to automotive electric dual-fan systems

Description

The Flex-A-Lite Variable Speed Controller is an electric fan controller for automotive dual-fan systems. It features an adjustable activation temperature range of approximately 160-240°F and provides relay function that eliminates the need for external relays. The cooling fan control module starts fans at 60% power, reducing startup amperage and increasing fan speed to 100% as the engine coolant temperature increases. It also runs fans for up to 25 seconds after the vehicle is turned off to remove excess heat from the radiator. The controller comes with a thread-in temperature sensor, a max amp inline fuse, wiring and electrical terminals for most common applications using an electric radiator cooling fan or engine cooling fan. It also includes a 1/4-inch NPT threaded temperature probe with 3/8-inch and 1/2-inch thread adapters. With a 45-amp rating and compatibility with 12-volt systems, these car parts are a reliable and efficient option for controlling engine cooling fans. The auto parts fan controller comes with a one-year manufacturer warranty, providing peace of mind for car enthusiasts who demand quality and reliability.

Brand: Flex-a-lite


Material: Metal, Plastic, Semiconductor


Item Weight: 16 ounces


Style: Modern


Lower Temperature Rating: 160 °F


Lower Temperature Rating: 160 °F


Maximum Supply Voltage: 12 volts_of_direct_current


Measurement Accuracy: ±2%


Measuring Range: 160 - 240 °F


Mounting Type: Threaded


Output Type: electrical signal


Response Time: 25 seconds


Specific Uses For Product: automotive electric fan control, temperature-based fan speed adjustment


Upper Temperature Rating: 240 °F


Material Type: Metal, Plastic, Semiconductor


Style Name: Modern


Item Weight: 16 ounces


Brand Name: Flex-a-lite


Model: 31163


UPC: 088657311632


Global Trade Identification Number: 32


Manufacturer: Flex-a-lite


Warranty Description: Warranty, Parts Parts, Warranty, Labor Authorized Dealer - Full Manufacturer's Warranty Applies


Unit Count: 1 Count


Included Components: Wire, terminals


Item Type Name: Variable Speed Control Module with Threaded Temperature Sensor


Part Number: 31163


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Saturday, Aug 15

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews

    • Well designed works great - The kit has everything needed to install. Tech. support awesome!
I installed an older version of this in my car over 10 years ago. It was still working fine, but I didn't want to risk overheating, so I replaced it. Since I bought my first one the controller has been redesigned and is much improved. (Not that it was crappy before ;-) The fan speed ramps up and down over about a 10 degree range which is nice. It has a "soft" start so as to be easier on the charging system. Very important to me living in the south: It has a controller lead that can be wired to your AC compressor so that the fan comes on when the AC is running. This provides MUCH improved AC performance compared to my OEM fluid fan clutch. This feature alone made it worth installing for me! Tech. Support is available. It is speedy and knowledgeable. I spoke with AJ about some details of installing this on my "vintage" 1986 vehicle, and he was incredible helpful! All the parts that you will need are included in the kit, and he fuse block included is the most robust I have ever seen! I've had trouble in the past with the crappy fuse holders from the mass-market parts stores... I expect no trouble from this one! ... show more
Reviewed in the United States on November 1, 2021 by JimBob
    • High quality
Excellent fan controller assembly. instructions are clear and easy to follow. The hardest part was finding the space to mount it in my 1966 Mustang engine bay.
Reviewed in the United States on May 19, 2026 by Jon Byrom
    • Works reliably.
Works well with the Flex-a-Lite 180 fan. Little bit of humming when the fan spins up I assumed after soft start part. Does not bother me like other people The fan works lol. I accidentally ordered this one with the thread in temperature sensor not the probe that goes into the radiator. I wedge the thread and sensor between the bottom of the fan and the bottom of the radiator touching metal and it works fine and it's temporary placement whenever the radiator is not cooling enough the fan kicks on reliably. I do plan on getting an adapter that attaches to the radiator hose to wire in the temp sensor to the coolant flow of the engine outlet. Just waiting for that stuff to arrive. Comes with a 45 amp fuse I'm running a single flex a light 180 series s blade fan. It only draws 20 amps under peak load. This controller can definitely run two or more fans as long as you stay within the amp rating of this fan controller. Plenty of wire for my 2003 Toyota Tacoma V6 with some to spare. I've watched videos online to where people screw the fan controller directly into the plastic housing of the engine fan, I opted to attach the controller to the metal fan mounting brackets. I use the bigger metal ones not the skinny long ones. perfect mounting place. ... show more
Reviewed in the United States on November 23, 2025 by cory2006
    • Absolutely phenomenal
Wow. I was running a flex a lite compact controller in my 81 CJ8 that worked great until I recently upgraded my fan. I went from a fan that pulls 8 amps to one that needs 18.5. Big change. It was rated for up to a 20 amp fan but it started drifting the set temp as the vehicle ran for longer periods of time. I never knew if it would kick on at 180 or 198. Keep in mind the old controller was 5+ years old and had endured some pretty heavy duty off-roading in the Florida swamps. Even though it did drift, it never allowed the jeep to overheat which I appreciate. This new controller is just dreamy. Installation is straightforward and took about an hour and a half. I soldered every connection which takes time but is the only way to go imo. The soft start is especially nice. The 20 second run on after shutdown is also handy. I highly recommend this controller. ... show more
Reviewed in the United States on December 24, 2025 by Josh Newman
    • Overall pretty good
I called the tech line at Flex-a-lite before I bought it,and told them them I had a Derale two speed fan and wanted to know if it would work on it properly. Tech said it should work fine. (Note: Derale controler I bought was junk, did not work out box and tech support does not exist.) Unit installed fine, but fan chatteres when first starting. I believe this is due to 60 % starting current. The Derale fan is 13 inch in diameter, tried it on both speeds same result. Called the tech line to see if I was doing somethng wrong. Tech was very supportive, went throught installation process seems everything was right. After checking out found that all the connections were creating a lot of resistance. Cleaned the connections and checked with meter and fan only slightly chatters at start up. Controller works very well. Recommend to manufacturer to make leads from controller to battery in one long piece to elimate 2 splices. This will also make it look cleaner. ... show more
Reviewed in the United States on November 25, 2012 by Ldt51
    • Great fan controller for my 1971 442.
This fan controller was an easy install. It came with everything I needed to install. Instructions were pretty clear and easy on follow. I really like the slow start when it reaches temp and the 20 second run off after the ignition is turned off. The price is fair for what it all comes with.
Reviewed in the United States on October 27, 2025 by weissj62
    • Great product.
Has been working perfectly since install. (2) 12” derale fans on a 12v Cummins. Temp adjustment works great and the AC function works as intended. More expensive but more function. An all in one unit instead of doing 2 or 3 relays.
Reviewed in the United States on August 25, 2025 by Glen S.
    • FAILED LESS THAN A MONTH AFTER WARRANTY
I'm a master certified mobile electronics technician, over 35 years in the custom automotive field, restoration, custom fabrication, and electrical. I've always loved Flex-a-lite products until now. Module was installed on a well maintained 2001 Ford Ranger that still looks like the day we bought it. Decided to relieve the added stress from the factory fan and add my go to Flex-a-lite products. Installation was always straightforward, clean, and installed to look factory. However, the longevity of this unit doesn't leave me comfortable to put anyone behind the wheel with a Flex-a-Lite product. Keeping things cool is not what it's cracked up to be. Where did this go wrong? I can guarantee the installation 100%.... that's my job and my responsibility to provide not only myself but my customers what was supposed to be a quality product. One failure leaves the door wide open for multiple failures. I'm requesting to my customers whom I've installed any Flex-a-lite products to whether they purchased the modules themselves or not to bring them in and swap them for another product. All it takes is one failure, excessive overheating, and a family member stranded in this Texas heat to realize that the quality has gone down hill. Thank you Flex-a-lite for the quality in what used to be years ago, but not where it 's heading today. ... show more
Reviewed in the United States on July 18, 2024 by CP DESIGNS

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