Choosing the Best Flex-a-lite Fan Controller for Your Vehicle

2012 May 24
by admin

Flex-a-lite fan controllers are much more than just a relay for your electric fans. They turn the electric fans on and off, most of them provide the ability to adjust the temperature at which the fans turn on and almost all of them take the place of relays that other brands of fans require.

Many of our Flex-a-lite electric fans include a Flex-a-lite fan controller already, but the fans are also available without any controls.

Here's a breakdown of what each of our controllers do so you can choose the one that's best for you...:

The Adjustable Temperature Sensor is Flex-a-lite part number 31147. In addition to acting as a relay, it lets you vary the temperature at which the fan or fans turn on from approximately 180-240 degrees Fahrenheit with a simple knob from. It uses a stainless steel probe that inserts in the radiator fins to sense engine-coolant temperature. This module is rated to manage 20-amps at fan start-up. The Flex-a-lite Cooling Control Module is ideally suited for many Flex-a-lite single fans such as the Trimline, LoBoy and Lo-Profile product lines.

 The Cooling Control Module is Flex-a-lite part number 31149. It provides the same function as the 31147 Cooling Control Module with a higher amperage rating (40-amps at fan start-up). It also has an integrated air-conditioning control which turns the electric fan on whenever the air conditioning is on. The Flex-a-lite Cooling Control Module is ideally suited for any Flex-a-lite single fan, and can be also be used with some of our lower-amperage dual fans such as part numbers 330, 365 or 412. It should not be used with fans that draw 28 or more continuous amps, such as Flex-a-lite part numbers 290, 295 or 480.

The Variable Speed Control also acts as a relay and lets you vary the temperature at which the fan or fans turn. Additionally, it sets the fan speed from 60-100 percent, depending on the coolant temperature. This reduces the electrical load when the fans first start, and only draws the amperage needed for the temperature of the engine coolant. This controller also keeps the fan or fans running for 30 seconds after the key is turned off. This module is rated to manage more amperage than the Cooling Control Module; 45-amps at fan start-up. There are several part numbers available:

Part # 31163: Variable Speed Control with the threaded sensor

Part # 31165: Variable Speed Control with the stainless steel temperature probe

The Variable Speed Controllers can be used with any Flex-a-lite electric fan; single or dual.

Additionally, we offer two versions of the Variable Speed Controllers with a feature that we call Quick Start: They start the fans at 100 percent power instead of varying the power to the fans between 60-100 percent.

Part # 31173: Variable Speed Control -- Quick Start with the threaded sensor

Part # 31174: Variable Speed Control -- Quick Start with the stainless steel temperature probe

All of our electric fans are designed to work with our Variable Speed Controllers – both single and dual fans. You only need one fan controller for Flex-a-lite dual fan setups.

Auxiliary Switch (Flex-a-lite part # 31148) lets you control or override the electric fan function. This switch can be wired to turn on a fan regardless of the engine temperature (overriding the temperature control feature in the Flex-a-lite controller) or it can be wired to turn the electric fan off (useful for water crossings during off-roading). The switch has a 10-amp rating, and it can be used with Flex-a-lite controller part numbers 31149, 31163, 31165, 31173 and 31174.

At Flex-a-lite-blog.com, you can learn how to install an adjustable thermostat fan controller, complete with a video.

18 thoughts on “Choosing the Best Flex-a-lite Fan Controller for Your Vehicle”

  • Scott
    Scott May 24, 2012 at 6:36 am

    Great article! I've been confused by the different controllers offered by Flex-a-lite, and this makes it easy to see what the differences are. Thanks!

    Reply
  • Mike Zike
    Mike Zike May 26, 2012 at 3:06 am

    I agree Great Article and Installation video.

    Reply
  • Ronald Gaspard
    Ronald Gaspard June 13, 2012 at 7:47 am

    I installed your fan control part # 31165 a few weeks ago on my 2006 Saab 9/7X. (Trailblazer) It works flawlessly! However I now have a check engine light. ( fan clutch speed failure ). It had an electrically operated fan clutch from the factory. Do you have a cure for check engine light? Or know of a solution. I hate the light being on, but love the electric fan.

    Reply
    • therealcoleq
      therealcoleq June 13, 2012 at 7:49 am

      Thanks for the feedback on the fan. Please call 800-851-1510 and ask for David Heutmaker. He'll talk through the check engine light issue and see if there is a solution. Thanks!

      Reply
  • jim kosmyna
    jim kosmyna June 20, 2012 at 10:53 am

    Just installed a 31165. With engine cold the fans come on 60% at startup! Adjust the screw and fans still run. I bypassed the wire to the ignition switch and ran directly to battery. Would this be the problem or is it a Faulty controller? If I must wire to ignition can I wire to the positive side of starter?
    Thanks for help.
    jim

    Reply
    • therealcoleq
      therealcoleq June 20, 2012 at 10:56 am

      Jim -- Thanks for buying our product! It's really hard to diagnose an issue like this on our blog. Please call our tech line at 800-851-1510. Ask for David or AJ and they'll walk through the troubleshooting. Thanks!

      Reply
  • Chuck
    Chuck August 6, 2012 at 4:32 pm

    After running a dual fan set up for two years one day the 30 amp in line fuse block melted down before blowing the fuse I've wired in a new heavy duty in line fuse block with a new 30 amp fuse in it has this happened to others ?

    Reply
    • therealcoleq
      therealcoleq August 6, 2012 at 11:06 pm

      Thanks for your question. However, this isn't the best place to work through technical issues. Please give us a call us at 800-851-1510 and we'll work through the many variable to determine what could have caused this. Thanks!

      Reply
  • dana
    dana September 1, 2012 at 3:58 pm

    I have a 2008 ford f150 that has an electric clutch on the OEM fan. Can I use the existing wiring to determine when my e-fan comes on. For instance, I am assuming the computer wants the fan engaged when certain temps are reached and when the AC is on but wouldn't it also turn the fan off when traveling at highway speeds? It seems like I could tap into the OEM wiring and use relays to turn the fans on and off. Am I on the right track and if so do you have any products that could help me?

    Reply
    • therealcoleq
      therealcoleq September 2, 2012 at 12:02 am

      We don't recommend that. The assumption with a clutch fan is that you have some fan speed even when the clutch is not engaged. And a clutch fan will activate at different conditions. It's best to use our Adjustable Temperature Controller for a single fan or our Variable Speed Controller for a dual fan setup (higher amperage). Both of these measure the actual coolant temperature for fan activation, and allow you to adjust what temperature the fan or fans turn on. They act as a relay, so no additional relay is needed, and they have a terminal to connect to the A/C to turn the fan(s) on whenever the A/C is on.

      Reply
      • dana
        dana September 5, 2012 at 3:38 pm

        What is the best way to have the fans not run when the A/C is on but you are driving at highway speeds?

        Reply
        • therealcoleq
          therealcoleq September 5, 2012 at 8:17 pm

          We're assuming that you're running one of our fan controllers. If you don't want the electric fans to turn on when the A/C is on at highway speeds, you'll have to disconnect the lead that turns them on whenever the A/C is on. With our controller, the fans will still turn on when the temperature of the coolant is hot enough to activate the fans, but they won't run whenever the A/C is on.

          Reply
  • AugS
    AugS November 18, 2012 at 6:42 pm

    Great informational page! Glad I found it. I plan on getting the control 31165 to run my dual flex fan 420. My question, Scenario: My car is running and the controller 31165 has not yet turned the fans on. If I turn on my a/c, does the a/c turn on the fans at 60%? Or does the a/c automatically turn on the fans at 100%? When running the a/c, does that override the temperature setting on the contoller?

    On the previous question referring to Dana: can't Dana just use a Flex aux switch #31148 and connect it to lead #5 on controller 31165? It's a manual turn off switch. Can't that be used to turn off the fans when the a/c is on at highway speeds?

    Reply
    • therealcoleq
      therealcoleq November 19, 2012 at 4:32 am

      When the A/C is turned on, the fans will come on at 60 percent and will increase speed as the temperature rises above the set point.

      As for Dana's question, manual off will override the entire system and shut the fans off whether or not there is a demand for them from another system such as the A/C. If it was used this way to turn off the fans on the highway, though, they would have to remember to turn the system back on when it's needed.

      Reply
      • AugS
        AugS November 19, 2012 at 5:32 pm

        Thanks for the info! I ordered my 31165 and should have it by Wednesday. Just a couple more questions. Straight out of the box, is the controller set at a certain temperature from the factory? I saw pictures of it and it doesn't have any temperature markings, just a adjusting screw.

        Also, if for some reason, the probe isn't working correctly, will the manual turn on switch turn the fans on at 100%?

        Reply
        • therealcoleq
          therealcoleq November 19, 2012 at 10:04 pm

          The controller does not come set at any specific temperature. There are not temperature markings on it because the exact temperature will vary slightly according to variables like where the probe is placed, what material the radiator is, etc.

          And, yes, the "manual on" will override the fans to 100 percent, whether or not they are already running.

          Reply
      • AugS
        AugS December 7, 2012 at 8:15 pm

        I received the my control kit 31165 and manual switch 31148. I'm not a professional installer but it doesn't seem that difficult as I looked over the instructions. A couple questions did come to mind as I'm looking this over. My kit came with 2 battery connectors but I see 3 lines going to the battery terminals, (1 neg, 2 positives). Am I missing something with the "thin red" wire going to the ignition wire #9?

        Also, on manual switch 31148, it shows connection 3 to a 12v source. Can I connect that wire straight to the battery?

        Reply
        • therealcoleq
          therealcoleq December 7, 2012 at 9:38 pm

          It's not too difficult to wire and install. The "thin red" wire that connects to the terminal 9 is connected to a switched ignition power source, not directly to the battery. Some people route the wire to the fuse block while others find a switched 12-volt source underhood. The ignition coil and alternator are NOT okay sources for this. Assuming that the manual override switch will be mounted inside the vehicle, it's better to connect it to the fuse block located in or under the dashboard.

          Reply
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