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Strange noise when electric brakes are plugged in.

Jo_chrisJo_chris Member Posts: 21
edited April 2016 in Trailer & Towing
This sound happens while driving with 7 pin plugged in most of the time. When unplugged sound gone. Had brakes checked by local mechanic said all looked great. I am bringing  TV up to guy who installed brake control today to make sure everything is okay on that end. Everyone on this forum is so knowledgeable thought maybe someone might know what the problem could be. Drove our new 2016 T@B home from VT (we are in CT) and have only driven about 2 miles to mechanic.


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  • Jo_chrisJo_chris Member Posts: 21
    Was trying to post video of problem but having trouble.  Selected icon, went  to photo library, chose the video then nothing. Am I missing a step?
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  • ScottGScottG Administrator Posts: 5,557
    What sort of sound is it, and where is it coming from?
    2015 T@B S

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  • Jo_chrisJo_chris Member Posts: 21
    Tried to post a video but having technical difficulties, ha! The sound is coming from the wheel area and it sounds like a loud vibrating/humming.
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  • NomadNomad Member Posts: 7,209
    edited April 2016
    St_Bob - When I was watching vids to diagnose my brake problem, one said if you use an LED circuit tester (or volt meter), it will show current. If you use an incadesent version it won't but will glow brighter and brighter as you squeeze the emergency slide on the controller. As testing my brake controller ad sure enough, that's what I found. Need the resistance from the incadesent bulb supposedly.
    I'm not a voltmeter guy so maybe there's a way to test that resistence on it, don't know.
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  • Jo_chrisJo_chris Member Posts: 21
    edited April 2016
    Well we discovered the problem. CONSTANT VOLTAGE to the brakes, ST_Bob was right! I brought the TV up to the people who installed the Draw Tite controller they tested it but didn't do as Bob suggested (wish I had this information prior to going up there). Got home hooked up and The humming was still happening. Called a different place, Dave's RV in Danbury, CT and Dave Jr. told us to cut the brake wire on the activator, we did and the noise stopped so now we are headed up there next week to get a new brake controller (different brand) let's hope this one works. Dave Jr. in Danbury, Ct  knew exactly what the problem was by our discription over the phone, as did @ST_Bob. Thanks! Our local mechanic didn't know and he had the tv and trailer!
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  • ScottGScottG Administrator Posts: 5,557
    ST_Bob said:
    With your foot off the brake you should have very little current - not enough to light an incandescent bulb type tester.  LED or voltmeter will always show the small test current that tells the brake controller it's connected to the trailer.  I forgot about that - so thanks.
    By "current" I assume you mean voltage, right? (As opposed to amperage.)

    I have a good multimeter, do you know the ballpark values for expected voltage at the brake wire with and without the brakes applied? 
    2015 T@B S

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  • ScottGScottG Administrator Posts: 5,557
    Thanks, ST_Bob, I think...

    I understand your explanation regarding the voltage, and why a voltmeter will not necessarily indicate if the brake electronics are functioning properly. The incandescent test light seems the simplest approach, though the information it provides is not quantitative.

    Assuming the use of a multimeter robust enough to handle the current, would measuring amperage be a better way of quantifying the output at the brake wire? 
    2015 T@B S

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  • RatkityRatkity Member Posts: 3,770
    Ohhhhh I love science talk.... oscilloscopes! :)
    2017 820R Retro Toy Hauler from 2015 Tabitha T@B from 2009 Reverse LG Teardrop (but a T@Bluver at heart)
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  • ScottGScottG Administrator Posts: 5,557
    Seriously, I've always wanted an excuse to borrow an osillyscope and hook it up to something in my garage. I think ST_Bob gave me a great idea!
    2015 T@B S

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  • NomadNomad Member Posts: 7,209
    Yep, need some draw (resistance?) - When I thought my controller had gone south, while using either a voltmeter or LED type circuit tester, there would be juice and the LED would light. Half the people opinioned that was fine, the other it was bad. Watched a couple YouTubes, bought an incandescent bulb circuit tester and the controller turned out to be just fine.
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  • PhotomomPhotomom Member Posts: 2,217
    Guys, what about this doohickey for testing the wiring and the brake controller?

    http://www.amazon.com/Tekonsha-6562-Trailer-Emulator-Display/dp/B004BCA9B8/ref=sr_1_1?ie=UTF8&qid=1461613066&sr=8-1&keywords=Tekonsha+tester
    John and Henrietta, Late 2016 T@B S Max in Western New York
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  • NomadNomad Member Posts: 7,209
    Photomom - A incadescent circuit tester is $10-12.
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