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  1. #1
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    Poor braking, checked current flow with ammeter

    After reading some poor braking threads... I suffer from the same issue. I’ve pondered whether it was the tow vehicle or the trailer so I bought a clamp AC/DC ammeter to see what was going on (careful, a lot only measure AC).

    With the break away switch pulled, both left side brakes were about 5.7 amps each. The right side only saw about 2.5 amps each. It would appear the lamp cord used inside the axle from side to side sucks.

    I then tried the tow vehicle, engine running, manual 100% braking. Both left side was 2.7 amps each, right side was 1.2 amps each. That may explain the poor braking.

    For now I’ve ordered some 12awg wire to replace the axle tube wire. I’ll see if that equals out side to side, then I may look at the rest of the wiring. Just gaining an amp or two on the right side should improve braking at least a little bit! Most likely disc brakes will be a winter project.
    Trailer: 2019 Solitude S-Class 3740BH
    Old trailer: 2016 Outdoors RV Creekside 27DBHS (Sold)
    Old trailer: 2010 Heartland Sundance 3300RLB (always leaked, then rotted! Layout was good, but build was junk.)
    Old trailer: 1992 Prowler 5th 27.5N

    Truck: 2016 Ram 3500 Cummins Megacab 4x4 SRW Laramie Aisin
    Old truck: 2012 Ram 3500 Cummins Megacab 4x4 SRW Laramie 68RFE
    Old truck: 2003 Ram 3500 Cummins QuadCab 4x4 SRW Laramie 6spd

  2. #2
    Seasoned Camper ncitro's Avatar
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    In my experience, while the lamp cord is not great, I'd start with the connections. At the rally last year I had Lippert out to look at nine expecting them to have grease issues, only to find one axle not getting power. He found a bad connection, and they've been rock solid ever sense.
    2018 Reflection 28BH
    2019 F350 Platinum 6.7L LB 4x4

  3. #3
    Site Sponsor Cate&Rob's Avatar
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    Quote Originally Posted by bcdiesel View Post
    With the break away switch pulled, both left side brakes were about 5.7 amps each. The right side only saw about 2.5 amps each.

    I then tried the tow vehicle, engine running, manual 100% braking. Both left side was 2.7 amps each, right side was 1.2 amps each.
    Hi bcdiesel,

    Per the Lippert manual (I assume Dexter is similar, if you have Dexter brakes) full-apply amperage for each wheel magnet is 3 amps. When you were measuring current on the left side, you may have actually been measure the current draw for two brakes because the wiring goes first to the left side and then across the axle to the right side.

    Since you are getting more-or-less the correct current with the break-away switch pulled, the question becomes . . . why are you only getting half this current from the regular brake apply circuit? Checking voltage drop with brake-apply at each wheel, with both break-away and regular apply might shed some light on this.

    And yes . . . disc brakes will definitely solve this problem .

    Rob
    Cate & Rob
    2015 Reflection 303RLS

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    Site Team xrated's Avatar
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    If you are truly looking to find the current draw on the brakes, use your clamp-on ammeter to measure each individual set of lines going to each wheel....not the entire line going from the breakaway switch to the entire system. At each wheel is two wires going to the individual brake magnet/solenoid for THAT wheel. Readings taken like that will show you what each individual magnet's current is. If there is more than say 5% difference between any of them, you most likely have a wiring issue (read splice/connection) or the magnet itself at an individual wheel. All four or six wheels are hooked up in parallel, which means that one should not affect the others if there is an issue with one or more wheels
    2016 F350 CrewCab Dually
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  5. #5
    Seasoned Camper
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    Quote Originally Posted by Cate&Rob View Post
    Hi bcdiesel,

    Per the Lippert manual (I assume Dexter is similar, if you have Dexter brakes) full-apply amperage for each wheel magnet is 3 amps. When you were measuring current on the left side, you may have actually been measure the current draw for two brakes because the wiring goes first to the left side and then across the axle to the right side.

    Since you are getting more-or-less the correct current with the break-away switch pulled, the question becomes . . . why are you only getting half this current from the regular brake apply circuit? Checking voltage drop with brake-apply at each wheel, with both break-away and regular apply might shed some light on this.

    And yes . . . disc brakes will definitely solve this problem .
    Rob
    I took another look this morning and yes... I clamped to the wrong spot at each left side wheel and got the current of both sides there. So math works out to Left side of 3.2 amps each compared to 2.5 amps each on the right side from break away. With truck works out to 1.5 amps left and 1.2 amps right. Not as bad as a difference from my first post, but still shows a different from side to side via the axles tiny wiring (and the difference increases upon higher current which for sure points to wire gauge). Obviously shows a problem with braking ability from the tow vehicle, whether its the tow vehicle or trailer wiring or both I'm not sure for now. Will start with the axle wiring and will move forward from there.
    Trailer: 2019 Solitude S-Class 3740BH
    Old trailer: 2016 Outdoors RV Creekside 27DBHS (Sold)
    Old trailer: 2010 Heartland Sundance 3300RLB (always leaked, then rotted! Layout was good, but build was junk.)
    Old trailer: 1992 Prowler 5th 27.5N

    Truck: 2016 Ram 3500 Cummins Megacab 4x4 SRW Laramie Aisin
    Old truck: 2012 Ram 3500 Cummins Megacab 4x4 SRW Laramie 68RFE
    Old truck: 2003 Ram 3500 Cummins QuadCab 4x4 SRW Laramie 6spd

  6. #6
    Site Sponsor Cate&Rob's Avatar
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    @bcdiesel,

    If you have a high resistance in the supply to the brakes (small gauge wire or poor connection) there will be a significant voltage drop. Have you checked voltage at each brake? The wires across the axle are small gauge, but this is what they use on all axles and these wires are only carrying 3 amps max. Voltage should stay close to battery voltage with a 3 amp draw unless there is high resistance in the circuit somewhere.

    Rob
    Cate & Rob
    2015 Reflection 303RLS

  7. #7
    Seasoned Camper
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    I replaced the wire in the axles today. I installed 12awg and found that it barely fit through the plastic grommets. Larger gauge wire would not fit unless the plastic grommets were removed. I also opened up a couple factory crimp joints to see what they looked like; they were simply covered in heat shrink but it appeared moisture still got in. The axle wire already showed corrosion with the copper turning black. I soldered all my new connection points and used adhesive filled heat shrink to cover over. With the current meter to check, side to side measurements are now equal. All four wheels get the same current when tested with the break away switch (the highest possible current). Now just need to troubleshoot the truck brake supply feed!

    Picture below shows the factory crimps, my 12awg wire and the tiny factory axle wire (which had two insulating jackets). Of note I had to used the smallest wire stripper hole to strip the factory wire... must be 18-20awg if I had to guess.
    Click image for larger version. 

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    Trailer: 2019 Solitude S-Class 3740BH
    Old trailer: 2016 Outdoors RV Creekside 27DBHS (Sold)
    Old trailer: 2010 Heartland Sundance 3300RLB (always leaked, then rotted! Layout was good, but build was junk.)
    Old trailer: 1992 Prowler 5th 27.5N

    Truck: 2016 Ram 3500 Cummins Megacab 4x4 SRW Laramie Aisin
    Old truck: 2012 Ram 3500 Cummins Megacab 4x4 SRW Laramie 68RFE
    Old truck: 2003 Ram 3500 Cummins QuadCab 4x4 SRW Laramie 6spd

  8. #8
    Seasoned Camper
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    Had the truck in for service today... while waiting I did some more online research and found that a TSB was generated for Ram trucks in October of 2016 for trucks built before April 2016 (mine was Feb 2016 so it applied). This TSB is for poor or no braking if the user plugs the trailer in before the truck is started or engine running. Others online stated this TSB made a big difference in braking output. So... I had TSB 08-082-16 done today. And to my surprise I was charged $32 for the .2 hours labour to install this TSB since my truck is just past its 3 year warranty (this apparently is not considered powertrain). I've already emailed Chrysler Corporate complaining about having to pay to fix an obvious factory software mistake. I look forward to their response.

    TSB scanned below as attachment...

    Next I decided to test the braking current plugged into the truck. I did this with engine off, ignition on run. Only tested the front left trailer tire current each time. I not only pressed the truck brake pedal hard I also manually pressed 100% braking. I did this to try and get the maximum braking current possible from the truck while trying difference trailer types in the settings.

    My results:
    Heavy trailer: 1.37 amps
    Light trailer: 1.85 amps
    Light electric over hydraulic: 1.37 amps
    Heavy electric over hydraulic: 1.67 amps
    break away switch: 2.96 amps

    As can be seen above... the lowest amperage above was in heavy trailer mode or light electric over hydraulic. Light trailer setting put out more amps! Talk about counter intuitive. This is driveway testing only. I have not pulled the trailer testing light vs heavy.
    Attached Thumbnails Attached Thumbnails TSB.PDF  
    Trailer: 2019 Solitude S-Class 3740BH
    Old trailer: 2016 Outdoors RV Creekside 27DBHS (Sold)
    Old trailer: 2010 Heartland Sundance 3300RLB (always leaked, then rotted! Layout was good, but build was junk.)
    Old trailer: 1992 Prowler 5th 27.5N

    Truck: 2016 Ram 3500 Cummins Megacab 4x4 SRW Laramie Aisin
    Old truck: 2012 Ram 3500 Cummins Megacab 4x4 SRW Laramie 68RFE
    Old truck: 2003 Ram 3500 Cummins QuadCab 4x4 SRW Laramie 6spd

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