Low voltage on break controller

Discussion in 'Going to the DARK SIDE' started by Sjm9911, Sep 22, 2019.

  1. Sjm9911

    Sjm9911 Well-Known Member

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    Ok so while towing the new TT i get a low voltage warning on my break controller. I assume that means not enough voltage to the trailor to activate the breaks, so no breaks. I know i need to test this. So , i figure test the voltage coming out of the 7 pin conecter first , to see if it has voltage? That way i can limit my problum to the TV or the TT. my question is, what voltage should ot be at? Around 12 volts at higest gain? Then , i guess i need to check the ground on the trailor. I have no clue where that would be. Any help , advice or name calling is appreciated! Thanks.
     
  2. SteveP

    SteveP Well-Known Member

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    Check the blue wires at the trailer axle, they may have been crushed or pinched between the axle and the frame.
     
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  3. Sjm9911

    Sjm9911 Well-Known Member

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    It all looks good , and newer and sealed. Actually much better then the pop up. I tried contact cleaner, and some q tips , will check tomorrow to see if that helped.
     
  4. Sjm9911

    Sjm9911 Well-Known Member

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    Ok so i followed the tralor wiring back, i found the main ground. I removed the screws, sanded the wire, screws and inside the terminals. The harness on the TT goes into a neet box on the front of the camper, all is right and tight. From there it goes into the sealed boady, and comes down next to the wheels. Thays where i found the main ground conection. I did find i fix by one of the axels that had wire nuts on it, the other 3 tires have crimp conections from the factory. I will remove and clean up the nut conections, tape it all up and hope that will fix it. I could only locate a factory wire harness on the TV, so no ground next to the 7 point conecter. I assume it travels stright to the battery, and front console. Im not good with car ellectrical stuff. Ive read not to solder the wires, thats why they use the crimps and wire nuts. Some on the i terwebs say the solder breaks with the bouncing of the trailor?
     
  5. SteveP

    SteveP Well-Known Member

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    There should be a white wire from the seven pin going directly to a screw on the inside of the frame rail. No way GM would pay for 15 ft. of wire when they can get by with 15 ins. Use a jumper cable from the pup frame to the truck frame and see if the low voltage indication goes away.
     
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  6. Sjm9911

    Sjm9911 Well-Known Member

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    I'll look again tomorow, but the rear of the 7 pin is encaused in a hard tube wire bundle, i ran my hands along it, no wires coming out. ( it could be next to one of the tie offs). I will try the jumper cable. I have to get a new multimeter, as i cant find any of the at least 4 i own, lol. Serves me right for not reorganizing my tools after moving 2 years ago.
     
  7. mpking

    mpking Well-Known Member

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    What brand/type of tow controller?
     
  8. mpking

    mpking Well-Known Member

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    Googling around, I'm seeing low voltage on the "Brake Controller" is that the control box (in the cab) is not getting 12v. IE, problem between Brake Controller and the Truck's 12V.
     
  9. Sjm9911

    Sjm9911 Well-Known Member

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  10. Sjm9911

    Sjm9911 Well-Known Member

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    It reads pl , wich according to the manual reads as power inturupion while break pedal is depressed.
     
  11. mpking

    mpking Well-Known Member

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    Either the ground to the Brake Controller, or the 12V sense from the brake switch is shorting.

    I'd recommend calling Tekonsha. They had a great troubleshooting phone support when I totally messed up my P3 hooking up to my highlander.
     
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  12. Sjm9911

    Sjm9911 Well-Known Member

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    Ok so i folliwed the wiring harness, i think. And found a ground under the drivers side door and cleaned it up, hope thats it, will test on wendsday to see. Does this look like the ground for the wiring harness? Or do i keep looking. I found the gas tank ground wire. And i think there must be one under the hood. 20190924_105737.jpg 20190924_110426.jpg
     
  13. Ladiesman

    Ladiesman Active Member

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    What makes you think its a ground problem and not a power problem.
     
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  14. Sjm9911

    Sjm9911 Well-Known Member

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    It gets power then cuts out. Just figure the pop up worked fine, the TT has a lot more stuff to power. Just a guesstimate at this point. Figure easier to try this first and test later. It works fine in park. Just not when rolling and using the breaks. So testing might find the same, i also checked the wore conections, and they seam ok. And no noticable broken wires.
     
  15. davekro

    davekro Active Member

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    When I cleaned up my ground to chassis connections I coated the surface, lug and bolt underside w/ dialectic grease. After bolting tightly I cleaned surfaces w/ acetone, then shot with rattle can primer. On my trailer cleaned connections to the frame, I did not prime as I may be messin' with them buggers again. ;o)

    If the Tekonsha controller is saying something like intermittent voltage, I'd crawl under the dash and closely examine the wire from controller that is tapped into the 'cold side' (return) of the brake switch. THAT is one connection. If it proves good, THEN go down the rabbit hole checking for ground issues. But I LOVE Steve's work around to create a known good ground from the TV frame to TT frame with jumper cables! (you dark sider ;o)
     
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  16. Sjm9911

    Sjm9911 Well-Known Member

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    Yea, cant find the volt meter, and had some time between other stuff , i will be doing the other grounds also, like 3 or 4 on the tv alone. Couldn't fint the dialectric grease( used to use it on my tin plate train tracks). I figure if i take it out and it works i can revisit the ground points in the future. Finding them is a bit of a puzzle. But i think i got it now. I haven't checked the controller conections as it worked fine with the pop up, thats on the list of stuff it could be, but i crimped it good and heat shrank the wires, more apt to be somewhere else. I figue now , ground, then if not I'll test, maybe the conections through the axels themselves, lots on how they fail. Then to the conteoller. Next is just to re wire. But both the TT and TV are 2012 or newer so im not thinking that yet.
     
  17. davekro

    davekro Active Member

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    I was a bit concerned when I saw wire nuts were used for connections right behind the drums. But since they seem to be working OK, I'll put off changing them to crimps until I have a reason to jack it up and pull the wheels. Funny how I add things to the Pup 'To Do List' 3 times as fast as I get things done! But... Labor of love and all. :eek:)
     
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  18. Sjm9911

    Sjm9911 Well-Known Member

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    I have those on one break also. I checked them there tight. Ill disconnect if needed later, but no need to do so yet. I wanted to solder them, but i read solder conwctions on trailors break easy, so they use the screw nuts. Who knows. , im still in the troubleshooting phase, so not taking apart crap and making another problum. Ill check the grounds first, at least if it doesn't work i elliminated it as a problem.
     
  19. Adam Connolly

    Adam Connolly Member

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    Your alternator might be going bad. When the contoller comes up with the low voltage code do your lights dim when you step on the brake. Or radio cuts out?
     
  20. Sjm9911

    Sjm9911 Well-Known Member

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    It was just checked and new belt installed last month. New battery also as mine was 6 years old. It has a volt meter on the dash, and its pinned at 12.6 volts( or a bit over the 12 volt mark.)
     

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