We all have encountered that blower motor or cooling fan that intermittently won't start up unless you thump it right? In this Quick Tip Tuesday video, I show you how to use a simple test light to check a blower motor for an open circuit and verify your problem. -Enjoy!
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50 thoughts on “Testing a 12v dc motor for an open with a test light”
  1. Avataaar/Circle Created with python_avatars Kivuli Panther says:

    By this principle, if you're checking for an open circuit, if you have a multimeter with a continuity test (beep) mode, hook it up to the connectors and just spin the motor. If the beep ever stutters it's bad. Yes?

  2. Avataaar/Circle Created with python_avatars tallica2002 says:

    Very useful especially if you're trying to find a good used from a junkyard

  3. Avataaar/Circle Created with python_avatars Andrew Smith says:

    I have a motor that will not run in truck. I can hook it straight to a battery and will run fine. I am not getting 12 volts at connector I am getting between 4 and 9.7 volts. I bought another end to eliminate that and it will run fine from the battery. I think that maybe the motor is bad and will run on high but the resistor is not putting out enough volts to run it.

  4. Avataaar/Circle Created with python_avatars powerram92 says:

    So that blower is bad then?

  5. Avataaar/Circle Created with python_avatars Marcus Cutright says:

    Test of the blower motor connector with the switch turned on high and only read 5 Volts,
    any ideas?

  6. Avataaar/Circle Created with python_avatars Wayne O says:

    Thanks Eric !

  7. Avataaar/Circle Created with python_avatars Martin Kucic says:

    Hail free tip Tuesday 🤚

  8. Avataaar/Circle Created with python_avatars Professor Graham Leach says:

    The bulb acts as a current limiting device. Very nice and widely useful in electronics, especially with antique tube amp restoration.

  9. Avataaar/Circle Created with python_avatars JOE Hyundai Tech says:

    Eric thanks so much for this video my focus cooling fan went out on me on friday nite coming home from work i used my power probe 3 to sent 12 volts to the motor and nothing well she does have 199k plus on it I guess I should not be surprised but i sure got my monies worth waiting for my new fan to come

  10. Avataaar/Circle Created with python_avatars Zilliver says:

    Why is the motor not running when using the test light to power it, but it will with just a wire?

  11. Avataaar/Circle Created with python_avatars Stevo Reno says:

    OFF the HOOK again Eric………………….GREAT Job !!!

  12. Avataaar/Circle Created with python_avatars Sm Ms says:

    👍 👍

  13. Avataaar/Circle Created with python_avatars Willie Gillie says:

    Very good tip. I’ll bet the dead spot is also were the motor comes to a stop and also where it starts.

  14. Avataaar/Circle Created with python_avatars MrsSunshine75 says:

    Thank you thank you thank you!!! Used this tech tip today to be sure it was the motor on an intermittent blower operation!

  15. Avataaar/Circle Created with python_avatars Dave Scruton says:

    And then there is a meter in resistance. …..no car battery required, or toss it on a scope.

  16. Avataaar/Circle Created with python_avatars Len in MI says:

    Volt meters will work also.

  17. Avataaar/Circle Created with python_avatars JustAnother IrishMan says:

    First time I seen this was on Richard Mc Cuistian`s channel its a brilliant test. Thank you Eric 🙂

  18. Avataaar/Circle Created with python_avatars Charles L says:

    Awesome Eric.

  19. Avataaar/Circle Created with python_avatars greenscobie86 says:

    Awesome tip. Thank you!

  20. Avataaar/Circle Created with python_avatars Joachim Johan says:

    NAIS!!!!

  21. Avataaar/Circle Created with python_avatars Thomas Pigg says:

    When I say this I'm not trying to be rude or facetious, but that information is totally "bomdiggity" (AWESOME). Hope it keeps a little green in someone's pocket instead of going out and buying a fan if it's not really needed. Thank You Sir.

  22. Avataaar/Circle Created with python_avatars bart dabi says:

    love that… every day is a learning curve… thank you Eric for sharing your knowledge I really learn a lot from you. Greetings from Poland. 🙂

  23. Avataaar/Circle Created with python_avatars wyman lei says:

    what about the pwm output blower motor, how do you test it ?

  24. Avataaar/Circle Created with python_avatars Chevy Life 2020 says:

    It's monday rite. Lol

  25. Avataaar/Circle Created with python_avatars FredFlintstone21 says:

    Thank you for this tip! I smashed the like and added the video to my favorites!

  26. Avataaar/Circle Created with python_avatars mark lavrack says:

    Thanks for this info very helpful. Just getting ready to pull another blower motor. Hey was wondering if you could show us how to change the brushings in these motors. The motor I am about to pull is from saab 95 and they want 400.00 for the new motor and assembly.

  27. Avataaar/Circle Created with python_avatars movieguy73 says:

    I gotta get me one of them scopes on a rope.

  28. Avataaar/Circle Created with python_avatars 23nesto23 says:

    Great videos. You mentioned on one of your previous videos about taking a class. Any suggestions on what site you recommend to take courses?

  29. Avataaar/Circle Created with python_avatars Cassius Puckett says:

    Good demonstration, Erick. But one question, why test? If motor has bad spot, just replace it. Their not rebuildabel.

  30. Avataaar/Circle Created with python_avatars mai chispita says:

    buena enseñanza amigo

  31. Avataaar/Circle Created with python_avatars 1quickchevy2 says:

    I love me some free tip Tuesday's.

  32. Avataaar/Circle Created with python_avatars Danny Compton says:

    That is a handy tip! Thanks for sharing.

  33. Avataaar/Circle Created with python_avatars gto 55 says:

    If there was a mechanics hall of fame you would absolutely be in it

  34. Avataaar/Circle Created with python_avatars Mike says:

    Great tip!

  35. Avataaar/Circle Created with python_avatars Antonio Claudio Michael says:

    Hey Eric O I have a question how did you make your own store for your Amazon I'm trying to make my own Amazon store so people can looks at the recommended products but not sure how it works I'm new to the Amazon associate and affiliate account

  36. Avataaar/Circle Created with python_avatars ROTAXD says:

    Just got done dealing with that very same issue on the wifes Malibu. The original fan actually has to be cut out of those damn things.

  37. Avataaar/Circle Created with python_avatars Tim Wrenn says:

    Congratulation Eric! you made it to Motor Age Enews!!

  38. Avataaar/Circle Created with python_avatars jake ounce says:

    Sweet!!

  39. Avataaar/Circle Created with python_avatars Benjamin Stockton says:

    Good tip eric o.

  40. Avataaar/Circle Created with python_avatars Z71Ranger says:

    Good to know! Thanks for your Videos…

  41. Avataaar/Circle Created with python_avatars Jeffry Blackmon says:

    Good tip. Thanks for recording.

  42. Avataaar/Circle Created with python_avatars Andy Ostensen says:

    what was the test light grounded to so the motor wouldn't run?

  43. Avataaar/Circle Created with python_avatars Kelly t says:

    Nice video.

  44. Avataaar/Circle Created with python_avatars Carlos Maurencig says:

    Great tip, simple, fast, great video

    Thank You

  45. Avataaar/Circle Created with python_avatars jr neff says:

    thk you super helpful

  46. Avataaar/Circle Created with python_avatars dan andy says:

    Great tip. I can't believe that after a lifetime of working on cars and other mechanical things I did not know that. Thanks.

  47. Avataaar/Circle Created with python_avatars Joe R says:

    Thanks, ​Eric!

  48. Avataaar/Circle Created with python_avatars Hola! Digital Monkey says:

    Great tip! Thanks!