In a previous video I showed you what a failing blower motor looks like using the U-Scope now with the new motor installed you get to see what "good" looks like. -Enjoy!
*Automotive Oscilloscopes: Waveform Analysis* - Great book to start w/ IMO :
*uScope Basic Kit*
*uScope Master Kit*
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48 thoughts on “Diagnosing an intermittent blower motor part ii”
  1. Avataaar/Circle Created with python_avatars mike kotarba says:

    Nice video showing a known good waveform. Was the the known good shown with the same time base per screen or time per division? Thanks for he tip on the waveform analysis book.

  2. Avataaar/Circle Created with python_avatars Dustin Bennett says:

    You mite already know this but with there is a quick setting to set up the uscope and the amp clamp. Under the menu choose presets, highlight amp, left or right click till you see low amp in top right hand corner, press OK and hold till it loads. If successful it will say 100:1A in top left hand beside battery. That will have it set up for the 20A (100mV/A) scale. That way the amps will read right. Love the uscope!

  3. Avataaar/Circle Created with python_avatars Upallnight says:

    My local True Value Hardware store use to carry replacement brushes for almost any type of electrical motor, however, with the Big Box Home stores like Home Repo, or LOWES they basically drove the mom and pop hardware store out of business. It was a sad day when they closed.

  4. Avataaar/Circle Created with python_avatars ET Don says:

    I believe Fan On High = Bypass all resistors = Full Beans. lol

    Happy Holidays to you and your family, Mr. O

  5. Avataaar/Circle Created with python_avatars Larry H says:

    That's a pretty cool way to analyze a motors performance. That little scope is the smallest DSO I've seen! Not having a portable scope my method for diagnosing this type of intermittency would be to run a set of wires from the blower and plug them into my micronta (Radio Shack) analog multimeter set to dc volts and set on the passenger seat. No fluctuation in supply voltage then the motor is toast.

    That said believe me I like the more scientific approach for troubleshooting electronics and I need a smaller, more portable DSO. I'm not sure if you have an electronics background Eric but your basic knowledge of electronics is pretty impressive!

  6. Avataaar/Circle Created with python_avatars ricky johnson says:

    As someone in the industry I appreciate your videos, I learn something from videos on even the simplest of jobs and I thank you for that…but I’ve gotta ask, It seems like you run a fairly busy shop. How do you manage to find the time to make so many detailed videos while running a business, do your customers pay for this content to some extent?

  7. Avataaar/Circle Created with python_avatars James Stafford says:

    Hey Mr Eric, I have a video that you might consider doing. Example, I own 2002 Ford F-150 King Ranch and I would like to know how to change the wiring for the factory fog lights. They come on only when headlights are on and in the low beam setting. I'd like to wire them to come on with factory switch, but without the headlights having to be on, nor having them cancel out when you trigger the high beam on. Thanks and you were amazing with the video with Marie giving Mrs Amber the Ford Fusion. God bless you and your family this holiday season.

  8. Avataaar/Circle Created with python_avatars madmaxsaturn says:

    That's my car! I like it but the the 2000 rpm idle when it's cold outside is annoying. It's really noisy and i leave early for work. My neighbors must love me.

  9. Avataaar/Circle Created with python_avatars Marshallz79 says:

    Hey Eric, what amp clamp do you use with the uscope?

  10. Avataaar/Circle Created with python_avatars Randy Gould says:

    great follow up video

  11. Avataaar/Circle Created with python_avatars Scott B says:

    Thanks for the "known good" trace. Good f/u.

  12. Avataaar/Circle Created with python_avatars ww_big_al says:

    Very good Eric. Never thought of troubleshooting a motor by current monitoring. As for your ripples in the good motor; When the brushes only touch one copper piece, current only flows through one winding. When the brush bridges the commutator gap the current flow increases because it is now flowing through 2 wingdings. Hence your ripple.
    As with others you have taught me a lot with your videos. Please keep up the good work. Merry Christmas to you and the family.

  13. Avataaar/Circle Created with python_avatars Nelson Narciso says:

    You da man

  14. Avataaar/Circle Created with python_avatars Arnold7221 says:

    Makes perfect sense, seeing the commutator and brushes. And seeing the scope current intermittent/soliod pattern. Again thanks I learned something here.

  15. Avataaar/Circle Created with python_avatars Gizmo42Rodeo says:

    Check Ace Hardware for motor brushes. I was surprised to see them there a few months ago when I was looking for something else.

  16. Avataaar/Circle Created with python_avatars Jesse C says:

    You can find all kinds of generic brushes on McMaster-Carr, that place is amazing if you really need something and have no clue where to get it, they have just about every size nuts bolt seal gasket hose clamp bearing and brush you could ever ask for.

    That being said I'm not really sure how you'd find the right sized brush, you could probably get close and guesstimate and it'd work alright as long as the dimensions were close. I would say definitely not worth the trouble or potential that the replacement would be missing a key or groove etc that held the brush in place, but on the other hand sometimes you need a brush for something you can't find that isn't made anymore.

  17. Avataaar/Circle Created with python_avatars Alan Matthews says:

    Bought the book.
    Question, can I use my vantage pro with this?

  18. Avataaar/Circle Created with python_avatars George Travers says:

    The commutator on the old motor is too worn to install new brushes.

  19. Avataaar/Circle Created with python_avatars HVAC1 says:

    Sweet very cool.

  20. Avataaar/Circle Created with python_avatars steve prichard says:

    Enhance, enhance! I could see the wires sticking through the carbon?

  21. Avataaar/Circle Created with python_avatars Przemek Potyra says:

    I can sell you a lot of new brushes. Typical part in Europe.

  22. Avataaar/Circle Created with python_avatars Duncan Mac says:

    Cool! Thanks for the videos.

  23. Avataaar/Circle Created with python_avatars Tom Dewey says:

    True root cause analysis which I like.

  24. Avataaar/Circle Created with python_avatars Norman Gallant says:

    Nice good scope patern

  25. Avataaar/Circle Created with python_avatars Smitty Smithsonite says:

    We all must channel our inner Ivan from time to time. I'm going to tear down a thermal switch for my oil & coal boilers that failed the other day, after I let the power cord hang down and rest on the section of the boiler that was 550°F. After I had walked away, BZZZZT!! I want to see what the contacts look like inside – there was infinite resistance across the switch no matter the position. Must've cooked 'em! Thing was 22 years old at a minimum anyway – I suspect even older than that.

    Nothing like troubleshooting 120v electrical problems at midnight on a Saturday night! The things a man will do to stay warm … 😁

    Must be that time of year. Just did a motor and switch in a '03 Taurus. My temporary fix of loading the motor up with silicone spray was extremely temporary, lol. At least it made the annoying squeal go away. The switch was your typical plastic piece of garbage with the thinnest copper contacts inside. Guess I can't criticize too much – it made it 15 years.

  26. Avataaar/Circle Created with python_avatars Donnie Robertson says:

    Great job again like always A+

  27. Avataaar/Circle Created with python_avatars Keith G says:

    My Mrs. walked in and remarked while was watching and said "I hope Santa brings him a new hat" – I tried to explain the hat on a man's head reflects the years experience in his business. Girls what do they know. Have a Merry Christmas Eric – – and leave the hat alone.

  28. Avataaar/Circle Created with python_avatars Mike Chiodetti says:

    VERY NICE! GREAT VIDEO! Scopes are amazing tools!
    Mr. O, I saw the video of the "Winning $5000.00," the car and all that was done to it, including Miss Marie's contribution to it. FANTASTIC!

  29. Avataaar/Circle Created with python_avatars Patrick Morrissey says:

    That was actually a decent explanation…. You were not wrong, in what you were saying… That's how it works….

  30. Avataaar/Circle Created with python_avatars Marco77acv DCS Brasil says:


  31. Avataaar/Circle Created with python_avatars A LeBlanc says:

    Yeah, the most stunning part of this is the fact that the motor could possibly be repaired…I guess they had some 1960s old new stock to get rid of at the factory. LOL Thanks Eric.

  32. Avataaar/Circle Created with python_avatars richard cranium says:

    any time i'd change a motor i'd press out the magnets unless they were glued in. most aren't just a spring clip holding them. lots of uses and they are fairly strong

  33. Avataaar/Circle Created with python_avatars Sam Rugtiv says:

    Good job well done. Eric merry Christmas my friend. Sam

  34. Avataaar/Circle Created with python_avatars Vicarod - says:

    Looks like you whacked your thumb pretty good…

  35. Avataaar/Circle Created with python_avatars Paul Marshall says:

    I believe you can still get brushes for starters, just the problem of finding the rite size

  36. Avataaar/Circle Created with python_avatars wizard1800 says:

    Well theres your probem lady! Great video and thanks for the follow up.

  37. Avataaar/Circle Created with python_avatars Rene Cherry says:

    We need to send Mr. O like a truck load of his favorite beer, and Miss Marie lots of Ice Cream!!

  38. Avataaar/Circle Created with python_avatars Eric Corse says:

    McMaster Carr sells brushes for those interested. I wouldn't be surprised a decent hardware store would stock them. That little scope is the trick.

  39. Avataaar/Circle Created with python_avatars Mike Goodman says:

    Happy Christmas to you and your family Eric. Thanks for all the videos and I hope you have a fantastic new year.

  40. Avataaar/Circle Created with python_avatars Yvon Larocque says:

    hi love ur vids…keep up the great work you do…i do have a question for you if i may??…i have a 2003 dodge dakota with the 4.7 4×4 and am haveing issues with my motor, and it works great but now i cant control the heat and it is stuck on defrost only..ive seen vids on some dodge products where as the wire in the back came un-plugged and shjowed how to remove that part of the dash and re-plug but on mine id does not just pop off?? you have any tips??…ive been searching through ur files but have not found it yet…(help)…lol…thanks in advance…p.

  41. Avataaar/Circle Created with python_avatars joseph prosser says:

    My old Mercedes (OK Scotty Kilmer cool your jets) used to cut the blower fan when I took a right turn. I live in Scotland so ‘cooling’ is rarely needed but the lack of circulating warm air was sorely missed. It turned out that the fan motor brushes were sticking in their guides and when I took a right turn the transfer of weight of the armature caused it to shift enough on its bearings to disconnected the brushes from the commutator. Stripped out the motor, sprayed WD40 to lubricate the guides and it worked like a charm and has done so for over ten years.